#include "bits/stdc++.h" #define FOR(i,a,b)for(int i=(a);i<(b);i++) #define F0R(i,a)FOR(i,0,a) #define ROF(i,a,b)for(int i=(b)-1;i>=(a);i--) #define R0F(i,a)ROF(i,0,a) #define REP(a)F0R(_,a) using namespace std; int main() { cin.tie(nullptr)->sync_with_stdio(false); vector<string> a; int n, m; cin >> n >> m; F0R(i,n){ string s; cin >> s; a.push_back(s); } int mw = INT_MAX, mh = INT_MAX; for (int i = 0; i < n; i ++){ for (int j = 0; j < m; j ++){ if (a[i][j] == '1'){ int k = j; for (; k < m and a[i][k] == '1'; k ++); int w = k - j; mw = min(mw, w); j = k; } } } for (int i = 0; i < m; i ++){ for (int j = 0; j < n; j ++){ if (a[j][i] == '1'){ int k = j; for (; k < n and a[k][i] == '1'; k ++); int h = k - j; mh = min(mh, h); j = k; } } } if (mw == INT_MAX) cout << 0 << endl; else cout << 1ll * mw * mh << endl; }