#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define rep(i,s,e) for(int (i) = (s);(i) <= (e);(i)++)
#define all(x) x.begin(),x.end()

int H,W;
vector<vector<int>> f;

double calc(i64 x,i64 y){
  double ans = 0;
  rep(i,1,H){
    rep(j,1,W){
      if(f[i][j]){
        ans += sqrt((x - i) * (x - i) + (y - j) * (y - j));
      }
    }
  }
  return ans;
}
int main(){
  cin >> H >> W;
  f = vector<vector<int>>(H + 1,vector<int>(W + 1));
  rep(i,1,H){
    string s;
    cin >> s;
    rep(j,1,W){
      f[i][j] = s[j - 1] == '1';
    }
  }
  double res = 1e18;
  rep(j,1,W){
    res = min(res , calc(0,j));
    res = min(res , calc(H + 1,j));
  }
  rep(i,1,H){
    res = min(res , calc(i,0));
    res = min(res , calc(i,W + 1));
  }

  cout << fixed << setprecision(8);

  cout << res << endl;
}