#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
  #include "settings/debug.cpp"
#else
  #define Debug(...) void(0)
#endif
#define rep(i, n) for (int i = 0; i < (n); ++i)
using ll = long long;
using ull = unsigned long long;

int main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int h, w;
  cin >> h >> w;
  vector Grid(h, vector<char>(w));
  rep(i, h) rep(j, w) cin >> Grid[i][j];
  double ans = 1e18;
  for (int x = -1; x <= h; ++x) {
    for (int y = -1; y <= w; ++y) {
      if (!(x == -1 || x == h || y == -1 || y == w)) continue;
      double sum = 0;
      rep(i, h) rep(j, w) {
        double d = sqrt((x - i) * (x - i) + (y - j) * (y - j));
        if (Grid[i][j] == '1') sum += d;
      }
      ans = min(ans, sum);
    }
  }
  cout << fixed << setprecision(15) << ans << '\n';
  return 0;
}