#include<iostream>
#include<iomanip>
#include<queue>
#include<string>
#include<stack>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<cstring>
#include<cassert>
#include<ctime>
#include<algorithm>
#include<utility>
#include<map>
#include<set>
#include<vector>
#include<functional>

using namespace std;

#ifdef DEBUG
#define dprintf      printf
#define dout(x)      cout<<#x" = "<<(x)<<endl
#define darray(x,n)    {int i;rep(i,n)cout<<#x"["<<i<<"] = "<<*((x)+i)<<endl;}
#define dloop(i,s,g) for((i)=(s);(i)<(g);(i)++)
#define drep(i,n)    for((i)=0;(i)<(n);(i)++)
#define dstop()      scanf("%*c")
#else
#define dprintf      (1)?0:printf
#define dout(x)
#define darray(x,n)
#define dloop(i,s,g) if(1){}else
#define drep(i,n)    if(1){}else
#define dstop()      if(1){}else
#endif

#define F    first
#define S    second
#define pb   push_back
#define mp   make_pair

#define loop(i,s,g) for((i)=(s);(i)<(g);(i)++)
#define rep(i,n)    for((i)=0;(i)<(n);(i)++)
#define all(x)      (x.begin(),x.end())
#define in(T,...) T __VA_ARGS__; impl(__VA_ARGS__);
#define array(T,id,n) T id[n]; rep(i,n)cin>>id[i];

//#define int long long;
#ifndef int
#define INF  (0x7fffffff)
#else
#define LINF (0x7fffffffffffffff)
#endif

typedef  long long           ll;
typedef  unsigned            ui;
typedef  unsigned long long  ull;
typedef  pair<int,int>       i_i;
typedef  pair<ll,int>        ll_i;
typedef  pair<ll,ll>         ll_ll;
typedef  pair<double,int>    d_i;
typedef  pair<double,double> d_d;

void impl(){};
template <typename T,typename... TS >
void impl(T &head,TS &... tail)
{
  cin>>head;
  impl(tail ...);
}
#define UNION_FIND_MAX_N (112345)
int union_find_par[UNION_FIND_MAX_N];
int union_find_rank[UNION_FIND_MAX_N];

void init(int n)
{
  int i;
  for(i=0;i<n;i++)
    {
      union_find_par[i]=i;
      union_find_rank[i]=0;
    }
}

int find(int x)
{
  if(union_find_par[x]==x)
    return x;
  else
    return union_find_par[x]=find(union_find_par[x]);
}

void unite(int x,int y)
{
  x=find(x);
  y=find(y);
  if(x==y)
    return;
  if(union_find_rank[x]<union_find_rank[y])
    union_find_par[x]=y;
  else
    union_find_par[y]=x;
  if(union_find_rank[x]==union_find_rank[y])
    union_find_rank[x]++;
}

int nsame(int x,int y)
{
  return find(x)!=find(y);
}

typedef struct edge
{
  int u;
  int v;
  int cost;
  bool operator>(const edge&right)const
  {
    return cost>right.cost;
  }
  bool operator<(const edge&right)const
  {
    return cost<right.cost;
  }
}Edge;

signed main(void)
{
  int n;
  Edge edge[112345]={};
  int i,j,k=0;
  int sum=0;
  cin>>n;
  init(n);
  rep(i,n)rep(j,n)
    {
      cin>>edge[k].cost;
      edge[k].u=i;
      edge[k].v=j;
      k++;
    }
  sort(edge,edge+k);
  rep(i,k)
    if(edge[i].cost!=-1)
      if(nsame(edge[i].u,edge[i].v))
	unite(edge[i].u,edge[i].v),sum+=edge[i].cost;
  
  cout<<sum<<endl;    
  return 0;
}
#include<bits/stdc++.h>
#include<ctype.h>
# define pb push_back
#define fst first
#define sec second
#define For(i,a,b) for(int i=a;i<b;i++)
#define ll long long int
#define ull unsigned long long int
#define mod 1000000007
#define fo(i,n) for(ll i=0;i<n;i++)
#define endl "\n"
#define rev(i,n) for(ll i=n-1;i>=0;i--)
#define fo1(i,n) for(ll i=1;i<=n;i++)
#define boolsize 1000001
#define pi pair<ll,ll>
#define vi vector<ll>
#define vii vector<pi>
using namespace std;
template<typename T>
void showvector(vector <T> v)
{
    for(T x:v)
        cout<<x<<" ";
    cout<<endl;

}
template<typename T>
void showvector1(vector <T> v)
{
    ll n=v.size();
    fo1(i,n-1)
        cout<<v[i]<<endl;

}
template<typename T>
void showset(set <T> s)
{
    for(T x: s)
        cout<<x<<" ";
    cout<<endl;
}
template<class T>
void showvectorpair(vector<T> v)
{
    for(auto it=v.begin();it!=v.end();it++)
        cout<<it->first<<" "<<it->second<<endl;
    cout<<endl;
}
template<typename T,typename P>
void showmap(map <T,P> m)
{
    for(auto it=m.begin();it!=m.end();it++)
        cout<<it->first<<" "<<it->second<<endl;
    cout<<endl;
}
template<typename T>
bool comp(T a,T b)
{
    return (a>b);
}
template<class T>
bool comppair(T a,T b)
{
    if(a.first==b.first)
        return(a.second>b.second);
    return (a.first>b.first);
}
bool sameparity(ll a,ll b)
{
    return (a%2==b%2);
}
bool difparity(ll a,ll b)
{
    return !(a%2==b%2);
}
bool isprime(ll x)
{   if(x<=1)
     return false;
    for(ll i=2;i<=sqrt(x);i++)
    {
        if(x%i==0)
            return false;
    }
    return true;
}
bool iseven(ll x)
{
    return !(x%2);
}
bool isodd(ll x)
{
    return (x%2);
}
//vector <bool> prime(boolsize,1);
//void seive()
//{
//    ll n=boolsize;
//    prime[0]=prime[1]=0;
//    for(ll i=2;i<=sqrt(boolsize);i++)
//    {
//        if(prime[i]==1)
//        {
//            for(ll j=i*i;j<=n;j+=i)
//            {
//                prime[j]=0;
//            }
//        }
//    }
//}

/// check for test case before submitting
void vfun()
{
    ll n,k;
    cin>>n>>k;
    vi v(n);
    fo(i,n)
    cin>>v[i];
    sort(v.begin(),v.end(),comp<ll>);
    ll sum=0;
    fo(i,k)
    sum+=v[i];
    cout<<sum<<endl;

}

int main()
{
    #ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
    #endif
    ios_base::sync_with_stdio(0); ///cant use scanf, printf
    cin.tie(0);cout.tie(0); /// no longer auto flush cout before each cin, remove for interactive
    //cout << fixed << setprecision(11); /// no scientific output
    ll test=1;
    //cin>>test;
    while(test--)
    {

        //fun();
        vfun();
//         if(vfun())
//            cout<<"YES\n";
//         else
//            cout<<"NO\n";
    }
}
///before sub
/// check for value of zero and single input in array
///loop vars,1LL in mult, equal, one, bounds, int v ll, endl, finish taking inputs
/// check whether test cases are given or not


