H,W = map(int,input().split())
P = [input() for _ in range(H)]
ans = 10 ** 8
for h in range(H):
    for w in [-1,W]:
        tmp = 0
        for i in range(H):
            for j in range(W):
                if P[i][j] == "1":
                    tmp += ((h-i)**2+(w-j)**2)**0.5
        ans = min(ans,tmp)
for w in range(W):
    for h in [-1,H]:
        tmp = 0
        for i in range(H):
            for j in range(W):
                if P[i][j] == "1":
                    tmp += ((h-i)**2+(w-j)**2)**0.5
        ans = min(ans,tmp)

print(ans)