def main():
    H, W = map(int, input().split())
    P = list(input() for _ in range(H))
    ans = float('inf')
    
    for h1 in range(1,H+1):
        for w1 in [0,W+1]:
            tmp = 0
            for h in range(H):
                for w in range(W):
                    if P[h][w] == '1':
                        tmp += ((h + 1 - h1) ** 2 + (w + 1 - w1) ** 2) ** 0.5
            ans = min(ans, tmp)

    for w1 in range(1,W+1):
        for h1 in [0,H+1]:
            tmp = 0
            for h in range(H):
                for w in range(W):
                    if P[h][w] == '1':
                        tmp += ((h + 1 - h1) ** 2 + (w + 1 - w1) ** 2) ** 0.5
            ans = min(ans, tmp)

    print(ans)




if __name__ == "__main__":
    main()