#include<bits/stdc++.h>
using namespace std;

#define int long long 

void read(int &x) {
    x=0;int f=1;char ch=getchar();
    for(;!isdigit(ch);ch=getchar()) if(ch=='-') f=-f;
    for(;isdigit(ch);ch=getchar()) x=x*10+ch-'0';x*=f;
}

void print(int x) {
    if(x<0) putchar('-'),x=-x;
    if(!x) return ;print(x/10),putchar(x%10+48);
}
void write(int x) {if(!x) putchar('0');else print(x);putchar('\n');}

#define lf double
#define ll long long 

#define pii pair<int,int >
#define vec vector<int >

#define pb push_back
#define mp make_pair
#define fr first
#define sc second

#define data asd09123jdf02i3h

#define FOR(i,l,r) for(int i=l,i##_r=r;i<=i##_r;i++)

const int maxn = 1e6+10;
const int inf = 1e9;
const lf eps = 1e-8;
const int mod = 1e9+7;

int n,m,b[maxn],l[maxn],r[maxn],ans,s[maxn],t[maxn];

int check(int x) {
    for(int i=1;i<=n;i++) {
        int c=x/m,d=x%m;
        int res=l[i]*min(b[i],d)+r[i]*max(0ll,d-b[i]),w=l[i]*b[i]+r[i]*(m-b[i]);// write(t[c+1]);
        if(c) {
            if(w<s[c]) res+=t[c];
            else res+=t[c+1]-w;
        }
        res-=ans;// printf("%I64d %I64d %I64d\n",x,i,res);
        if(res>=0) return 1;
    }
    return 0;
}

signed main() {
    read(n),read(m);
    for(int i=1;i<=n;i++) read(b[i]),read(l[i]),read(r[i]),ans+=b[i]*l[i],s[i]=b[i]*l[i]+(m-b[i])*r[i];
    sort(s+1,s+n+1,greater<int > ());
    for(int i=1;i<=n;i++) t[i]=s[i]+t[i-1];
    int l=0,r=n*m,ans=n*m;
    while(l<=r) {
        int mid=(l+r)>>1;
        if(check(mid)) r=mid-1,ans=mid;
        else l=mid+1;
    }
    write(ans);
    return 0;
}

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#pragma comment(linker, "/stack:200000000")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
//turn on extra precision
#pragma GCC target("fpmath=387")

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef string str;
typedef pair <int,int> pii;
typedef pair <ll,ll> pll;
typedef vector <int> vi;
typedef vector <ll> vll;
typedef vector <pii> vpii;
typedef vector <pll> vpll;

#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define ordered_multiset tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
#define mp make_pair
#define pb push_back
#define pob pop_back
#define pf push_front
#define pof pop_front
#define fi first
#define se second
#define fs first.second
#define ss second.second
#define ff first.first
#define sf second.first
#define newl '\n'
#define fbo find_by_order
#define ook order_of_key
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(),x.rend()
#define watch(x) cout << (#x) << " is : " << (x) << newl

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
vi dirx = {0,0,1,-1};
vi diry = {1,-1,0,0};
char to_upper (char x){
    if( 97 <= int(x) && int(x) <= 122) return char(x-32);
    if( 65 <= int(x) && int(x) <= 90) return x;
    return -1;
}
char to_lower (char x){
    if( 97 <= int(x) && int(x) <= 122) return x;
    if( 65 <= int(x) && int(x) <= 90) return char(x+32);
    return -1;
}
int numerize (char x){
    if(48 <= int(x) && int(x) <= 57) return int(x-'0');
    if(97 <= int(x) && int(x) <= 122) return int(x-96);
    if(65 <= int(x) && int(x) <= 90) return int(x-64);
    return -1;
}
bool isect (int l1, int r1, int l2, int r2){
    pii p1 = {l1,r1};
    pii p2 = {l2,r2};
    if(p1>p2)swap(p1,p2);
    return (p2.fi <= p1.se);
}
ll quickpow (ll num1, ll num2, ll MOD){
    if(num2==0)return 1%MOD;
    else if(num2==1)return num1%MOD;
    else{
        ll temp = quickpow (num1,num2>>1LL,MOD); ll res = ((temp%MOD) * (temp%MOD))%MOD;
        if(num2&1) res = ((res%MOD)*(num1%MOD))%MOD; return res;
    }
}
ll invmod (ll num, ll MOD){return quickpow (num,MOD-2,MOD);}
ll gcd (ll num1, ll num2){
    if(num1 < num2) swap(num1,num2); ll num3 = num1 % num2 ;
    while(num3 > 0){ num1 = num2; num2 = num3; num3 = num1 % num2;}
    return num2;
}
ll lcm (ll num1 , ll num2){return (ll) (num1/__gcd(num1,num2))*num2;}
// end of Template
int n,k;
double sum[200010];
double getsum(int l, int r){
    return sum[r] - sum[l-1];
}
int main(){

//    freopen("input.txt", "r", stdin);
//    freopen("output.txt", "w", stdout);

    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);

    int n,k; cin >> n >> k;
    for(int i = 1; i <= n; ++i){
        int p; cin >> p;
        int res = (p * (p + 1)) / 2;
        double RES = (res * 1.0) / (p * 1.0);
        sum[i] = sum[i-1] + RES;
    }

    double ans = 0;
    for(int i = k; i <= n; ++i){
        int l = i-k+1;
        int r = i;
        ans = max(ans,getsum(l,r));
    }
    cout << fixed << setprecision(10) << ans << newl;

    return 0;
}
