#include <bits/stdc++.h> using namespace std; template<typename T> void out(T x) { cout << x << endl; exit(0); } #define watch(x) cout << (#x) << " is " << (x) << endl using ll = long long; const int maxn = 2600; int n,m; string g[maxn]; int main() { ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0); cin>>n>>m; for (int i=1; i<=n; i++) { cin>>g[i]; g[i]="0"+g[i]+"0"; } g[0]=string(m+5,'0'); g[n+1]=string(m+5,'0'); int minW = m+10; for (int i=1; i<=n; i++) { int cur = 0; for (int j=1; j<=m+1; j++) { if (g[i][j]=='1') { cur++; } else { if (cur>0) { minW=min(minW,cur); } cur=0; } } } int minH=n+10; for (int j=1; j<=m; j++) { int cur = 0; for (int i=1; i<=n+1; i++) { if (g[i][j]=='1') { cur++; } else { if (cur>0) { minH=min(minH,cur); } cur=0; } } } // watch(minW); // watch(minH); int area = minW*minH; out(area); return 0; }