#include<cstdio>
#include<queue>
#include<utility>
#include<cstring>
#include<stack>
#include<algorithm>
#include<cmath>
#include<iostream>
#include<map>
#define MAX_N 100001
#define INF_INT 2147483647
#define INF_LL 9223372036854775807
#define REP(i,n) for(int i=0;i<(int)(n);i++)
void init(int n);
int find(int n);
void unite(int x,int y);
bool same(int x, int y);
int dx[4] = {1,0,0,-1};
int dy[4] = {0,1,-1,0};
using namespace std;
typedef long long int ll;
typedef pair<ll,ll> P;
bool cmp_P(const P &a,const P &b){
  return a.second < b.second;
}
int main()
{
  int H,W;
  double res=99999999,tmp;
  char P[52][52];
  cin >> H >> W;
  REP(i,H)
    cin >> P[i];
  REP(i,H+2)REP(j,W+2){
    if((i == 0 && j == 0) || (i == 0 && j == W+1) || (i==H+1 && j == 0) ||(i == H+1 && j == W+1))
      continue;
    
    if(((i == 0 || i == H+1) || (j == 0 || j == W+1))){
      tmp = 0;
      REP(k,W){
        REP(l,H){
          if(P[l][k] == '1'){
            tmp += sqrt((k+1-j)*(k+1-j)+(l+1-i)*(l+1-i));
            
          }
        }
      }
      res = min(res,tmp);
    }
  }
  printf("%.10lf\n",res);
  return 0;
}

int par[MAX_N];
int ranks[MAX_N];

//n要素で初期化
void init(int n){
  REP(i,n){
    par[i] = i;
    ranks[i] = 0;
  }

}

//木の根を求める
int find(int x){
  if(par[x] == x){
    return x;
  }else{
    return par[x] = find(par[x]);
  }
}

void unite(int x,int y){
  x = find(x);
  y = find(y);
  if(x == y) return ;
  if(ranks[x] < ranks[y]){
    par[x] = y;
  }else{
    par[y] = x;
    if(ranks[x] == ranks[y]) ranks[x]++;
  }
}

bool same(int x, int y){
  return find(x) == find(y);
}