def solve(H, W, field):
    reds = [(x, -1) for x in range(0, W)] + \
          [(x, H) for x in range(0, W)] + \
          [(-1, y) for y in range(0, H)] + \
          [(W, y) for y in range(0, H)]
    blacks = [(x, y) for x in range(0, W) for y in range(0, H) if field[y][x] == "1"]

    count = 0
    min = 25000 * 25000
    for red in reds:
        d = 0
        for black in blacks:
            d += pow(pow(red[0] - black[0], 2) + pow(red[1] - black[1], 2), 0.5)
        if d < min:
            min = d

    return "{:.8f}".format(min)

if __name__ == "__main__":
    l = input().split(" ")
    H, W = int(l[0]), int(l[1])
    field = [input() for _ in range(0, H)]
    print(solve(H, W, field))