#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#pragma GCC optimize("-O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#define pb push_back
#define fr(i, l, r) for(ll i = l; i <= r; ++ i)
#define rf(i, l, r) for(ll i = l; i >= r; -- i)
using namespace std;
using namespace __gnu_pbds;
template <typename T>
using _set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef int ll;
typedef pair<ll, ll> pll;
const ll oo = ll(1e9) + 10;
int main() {
//ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
ll n, m, ansx = oo, ansy = oo;
cin >> n >> m;
if(min(n, m) > 500)return 0;
char a[n + 1][m + 1];
fr(i, 1, n)fr(j, 1, m)cin >> a[i][j];
fr(i, 1, n){
fr(j, 1, m){
if(a[i][j] == '0')continue;
ll l = -1, r = -1, u = -1, d = -1;
fr(x, i, n){
if(a[x][j] == '0')break;
r = x;
}
if(r < 0)r = n;
rf(x, i, 1){
if(a[x][j] == '0')break;
l = x;
}
if(l < 0)l = 1;
fr(x, j, m){
if(a[i][x] == '0')break;
d = x;
}
if(d < 0)d = m;
rf(x, j, 1){
//cout << "u = " << u << " i = " << i << " x = " << x << " a[i][x] = " << a[i][x] << endl;
if(a[i][x] == '0')break;
u = x;
}
if(u < 0)u = 1;
ll a = r - l + 1;
ll b = d - u + 1;
//cout << "i = " << i << " j = " << j << "a = " << a << " b = " << b << " u = " << u << " d = " << d << endl;
ansx = min(ansx, a);
ansy = min(ansy, b);
}
}
//cout << ansx << ' ' << ansy << endl;
cout << ansx * ansy << endl;
}
/*
3 3
1 5 1
2 3
1 3 5
2 3
*/
