#!python
# -*- coding: utf-8 -*-


H, W = map(int, input().split())
grid = []


def get_time(x, y):
    t = 0
    for i in range(H):
        for j in range(W):
            if grid[i][j]:
                t += ((x - (j + 1)) ** 2 + (y - (i + 1)) ** 2) ** (1 / 2)
    return t


def main():
    for i in range(H):
        grid.append(list(map(int, input())))

    ANS = float('inf')

    for y in range(1, H + 1):
        ANS = min(ANS, get_time(0, y))
        ANS = min(ANS, get_time(W + 1, y))

    for x in range(1, W + 1):
        ANS = min(ANS, get_time(x, 0))
        ANS = min(ANS, get_time(x, H + 1))

    print(ANS)


if __name__ == '__main__':
    main()