#define _CRT_SECURE_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <vector>
#include <string>
#include <array>
#include <queue>
#include <deque>
#include <set>
#include <list>
#include <map>
#include <stack>
#include <utility>
#include <algorithm>
#include <numeric>
#include <cstdio>
#include <cstdlib>
#include <cmath>
#include <cctype>
#include <cstring>
#include <climits>
#include <bitset>
#include <random>
#include <functional>
#include <sstream>
#include <iomanip>

using namespace std;

#define rep(i, n) for(int i=0; i<(n); i++)
#define FOR(i, m, n) for(int i=(m);i<(n);i++)
#define sz(x) ((int)(x).size())
#define all(x) (x).begin(),(x).end()
#define SORT(x) sort((x).begin(),(x).end())
#define REVE(x) reverse((x).begin(),(x).end())
#define mp make_pair
#define pb push_back

typedef vector<int> VI;
typedef vector<string> VS;
typedef vector<vector<int>> VVI;
typedef pair<int, int> PII;
typedef long long LL;

int h, w;
char p[55][55];

double check(int x, int y) {
	double re = 0;
	rep(i, h)rep(j, w)if (p[i][j] == '1')re += sqrt((x - i)*(x - i) + (y - j)*(y - j));
	return re;
}

int main() {
	cin >> h >> w;
	rep(i, h)rep(j, w)cin >> p[i][j];

	double ans = 1000000;

	FOR(i, -1, h + 1) {
		FOR(j, -1, w + 1) {
			if (i == -1 || j == -1 || i == h || j == w) {
				double x = check(i, j);
				if (ans > x)ans = x;
				//printf("%d,%d -> %d\n", i, j, x);
			}
		}
	}
	printf("%.12f\n", ans);
}