H, W = map(int, input().split())
P = [input() for _ in range(H)]

def dist(x1, y1, x2, y2):
    return ((x1 - x2)**2 + (y1 - y2)**2)**0.5

res = float('inf')

for k in range(H):
    tmp = 0.0
    for i in range(H):
        for j in range(W):
            if P[i][j] == '1':
                tmp += dist(k + 1, 0, i + 1, j + 1)
    res = min(res, tmp)

    tmp = 0.0
    for i in range(H):
        for j in range(W):
            if P[i][j] == '1':
                tmp += dist(k + 1, W + 1, i + 1, j + 1)
    res = min(res, tmp)

for k in range(W):
    tmp = 0.0
    for i in range(H):
        for j in range(W):
            if P[i][j] == '1':
                tmp += dist(0, k + 1, i + 1, j + 1)
    res = min(res, tmp)

    tmp = 0.0
    for i in range(H):
        for j in range(W):
            if P[i][j] == '1':
                tmp += dist(H + 1, k + 1, i + 1, j + 1)
    res = min(res, tmp)

print(res)