#include <bits/stdc++.h>
#include <atcoder/fenwicktree>

using namespace atcoder;
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<int, ll> pil;
typedef pair<ll, int> pli;
typedef pair<double,double> pdd;
#define SQ(i) ((i)*(i))
#define MEM(a, b) memset(a, (b), sizeof(a))
#define SZ(i) int(i.size())
#define FOR(i, j, k, in) for (int i=j ; i<(k) ; i+=in)
#define RFOR(i, j, k, in) for (int i=j ; i>=(k) ; i-=in)
#define REP(i, j) FOR(i, 0, j, 1)
#define REP1(i,j) FOR(i, 1, j+1, 1)
#define RREP(i, j) RFOR(i, j, 0, 1)
#define ALL(_a) _a.begin(),_a.end()
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define X first
#define Y second
#ifdef jayinnn
#define TIME(i) Timer i(#i)
#define debug(...) do{\
    fprintf(stderr,"%s - %d (%s) = ",__PRETTY_FUNCTION__,__LINE__,#__VA_ARGS__);\
    _do(__VA_ARGS__);\
}while(0)
template<typename T>void _do(T &&_x){cerr<<_x<<endl;}
template<typename T,typename ...S> void _do(T &&_x,S &&..._t){cerr<<_x<<", ";_do(_t...);}
template<typename _a,typename _b> ostream& operator << (ostream &_s,const pair<_a,_b> &_p){return _s<<"("<<_p.X<<","<<_p.Y<<")";}
template<typename It> ostream& _OUTC(ostream &_s,It _ita,It _itb)
{
    _s<<"{";
    for(It _it=_ita;_it!=_itb;_it++)
    {
        _s<<(_it==_ita?"":",")<<*_it;
    }
    _s<<"}";
    return _s;
}
template<typename _a> ostream &operator << (ostream &_s,vector<_a> &_c){return _OUTC(_s,ALL(_c));}
template<typename _a> ostream &operator << (ostream &_s,set<_a> &_c){return _OUTC(_s,ALL(_c));}
template<typename _a> ostream &operator << (ostream &_s,deque<_a> &_c){return _OUTC(_s,ALL(_c));}
template<typename _a,typename _b> ostream &operator << (ostream &_s,map<_a,_b> &_c){return _OUTC(_s,ALL(_c));}
template<typename _t> void pary(_t _a,_t _b){_OUTC(cerr,_a,_b);cerr<<endl;}
#define IOS()
class Timer {
private:
    string scope_name;
    chrono::high_resolution_clock::time_point start_time;
public:
    Timer (string name) : scope_name(name) {
        start_time = chrono::high_resolution_clock::now();
    }
    ~Timer () {
        auto stop_time = chrono::high_resolution_clock::now();
        auto length = chrono::duration_cast<chrono::microseconds>(stop_time - start_time).count();
        double mlength = double(length) * 0.001;
        debug(scope_name, mlength);
    }
};
#else
#define TIME(i)
#define debug(...)
#define pary(...)
#define endl '\n'
#define IOS() ios_base::sync_with_stdio(0);cin.tie(0)
#endif

const ll MOD = 1000000007;
const ll INF = 0x3f3f3f3f3f3f3f3f;
const int iNF = 0x3f3f3f3f;
const ll MAXN = 100005;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

/********** Good Luck :) **********/
int main () {
    TIME(main);
    IOS();
    int n, q;
    cin >> n >> q;
    fenwick_tree<ll> bit(n);
    for(int i=0;i<n;i++){
        int p;
        cin >> p;
        bit.add(i, p);
    }

    while(q--){
        int t;
        cin >> t;
        if(t == 0){
            int p, x;
            cin >> p >> x;
            bit.add(p, x);
        } else {
            int l, r;
            cin >> l >> r;
            cout << bit.sum(l, r) << endl;
        }
    }

    return 0;
}
#include<bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)n;i++)
#define Rep(i,s,f) for(int i=(int)s;i<(int)f;i++)
using ll=long long;
using namespace std;


int bfs(vector<string> A,int H,int W)
{
	queue<pair<int,int>> que;
	vector<vector<int>> cost(H,vector<int>(W,-1));
	int lp=H*W;
	rep(i,H)
	{
		rep(j,W)
		{
			if(A[i][j]=='#')
			{
				que.push(make_pair(j,i));
				cost[i][j]=0;
				lp--;
			}
		}
	}
	int dir[4][2]={{1,0},{-1,0},{0,1},{0,-1}};
	int ret=0;
	while(lp!=0)
	{
		int n=que.size();
		rep(i,n)
		{
			pair<int,int> p=que.front();que.pop();
			for(auto d : dir)
			{
				int x=d[0]+p.first;
				int y=d[1]+p.second;
				if(0>x||x>=W||0>y||y>=H||cost[y][x]!=-1) continue;
				cost[y][x]=0;
				que.push(make_pair(x,y));
			}
		}
		lp-=que.size();
		ret++;
	}
	return ret;
}
int main()
{
	int H,W;
	cin>>H>>W;
	vector<string> A(H);
	rep(i,H)
	{
		cin>>A[i];
	}
	cout<<bfs(A,H,W)<<endl;
	return 0;
}
