// Ignut
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int INF = 1e9 + 123;
const int N = 2552;
int n, m;
int a[N][N];
bool used[N][N];
vector<pair<int, int>> delta = {{0, -1}, {0, 1}, {-1, 0}, {1, 0}};
bool Good(int i, int j) {
return i >= 0 && j >= 0 && i < n && j < m && !used[i][j] && a[i][j] == 0;
}
int sz;
int minh, maxh, minv, maxv;
void dfs(int i, int j) {
used[i][j] = true;
sz ++;
minh = min(minh, j);
maxh = max(maxh, j);
minv = min(minv, i);
maxv = max(maxv, i);
for (auto [di, dj] : delta) {
int ci = i + di, cj = j + dj;
if (Good(ci, cj))
dfs(ci, cj);
}
}
ll count_rectangles(vector<vector<int>> A) {
n = A.size(), m = A[0].size();
for (int i = 0; i < n; i ++)
for (int j = 0; j < m; j ++)
a[i][j] = A[i][j];
int res = 0;
for (int i = 0; i < n; i ++) {
for (int j = 0; j < m; j ++) {
if (used[i][j] || a[i][j] == 1) continue;
sz = 0;
minh = minv = INF;
maxh = maxv = -INF;
dfs(i, j);
if (sz == (maxv - minv + 1) * (maxh - minh + 1) && minh > 0 && minv > 0 && maxh < m && maxv < n)
res ++;
}
}
return res;
}
