import sys
input = sys.stdin.readline

def calc(x, y):
    res = 0
    
    for i in range(H):
        for j in range(W):
            if P[i][j]=='1':
                res += ((x-i)**2+(y-j)**2)**0.5
        
    return res

H, W = map(int, input().split())
P = [input()[:-1] for _ in range(H)]
ans = 10**18

for i in range(H):
    ans = min(ans, calc(i, -1), calc(i, W))

for i in range(W):
    ans = min(ans, calc(-1, i), calc(H, i))

print(ans)