#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include using namespace std; #if __has_include() #include using namespace atcoder; #endif #define GET_MACRO(_1, _2, _3, NAME, ...) NAME #define _rep(i, n) _rep2(i, 0, n) #define _rep2(i, a, b) for(int i = (int)(a); i < (int)(b); i++) #define rep(...) GET_MACRO(__VA_ARGS__, _rep2, _rep)(__VA_ARGS__) #define all(x) (x).begin(), (x).end() #define rall(x) (x).rbegin(), (x).rend() using i64 = long long; template bool chmin(T& a, const U& b) { return (b < a) ? (a = b, true) : false; } template bool chmax(T& a, const U& b) { return (b > a) ? (a = b, true) : false; } templateistream& operator>>(istream&i,vector&v){rep(j,v.size())i>>v[j];return i;} templatestring join(vector&v){stringstream s;rep(i,v.size())s<<' '<ostream& operator<<(ostream&o,vector&v){if(v.size())o<string join(vector>&vv){string s="\n";rep(i,vv.size())s+=join(vv[i])+"\n";return s;} templateostream& operator<<(ostream&o,vector>&vv){if(vv.size())o< using pq = priority_queue, greater>; int main() { int h, w; cin >> h >> w; vector table(h, vector(w)); for(auto& i : table) for(auto&j : i) cin >> j; int ans = 0; rep(i, h) { rep(j, w) { if(table[i][j]) { ans++; queue> que; que.emplace(i, j); while(!que.empty()) { auto [now_i, now_j] = que.front(); que.pop(); table[now_i][now_j] = 0; rep(di, -1, 2) { rep(dj, -1, 2) { if(abs(di) + abs(dj) > 1) continue; if(di == 0 && dj == 0) continue; int nex_i = now_i + di; int nex_j = now_j + dj; if(nex_i >= 0 && nex_i < h && nex_j >= 0 && nex_j < w) { if(table[nex_i][nex_j]) que.emplace(nex_i, nex_j); } } } } } } } cout << ans << endl; return 0; }