MOD = 10 ** 9 + 7
INF = 10 ** 11
import sys
sys.setrecursionlimit(100000000)
from itertools import product

def main():
    H,W = map(int,input().split())
    paper = [list(input()) for _ in range(H)]
    f = lambda y,x: sum(((y - i - 1)**2 + (x - j - 1)**2)**0.5 for i,j in product(range(H),range(W)) if paper[i][j] == '1')
    ans = INF
    for i in range(1,W + 1):
        ny,nx = 0,i
        ans = min(ans,f(ny,nx))
        ny,nx = H + 1,i
        ans = min(ans,f(ny,nx))
    for i in range(1,H + 1):
        ny,nx = i,0
        ans = min(ans,f(ny,nx))
        ny,nx = i,W + 1
        ans = min(ans,f(ny,nx))
    print(ans)
if __name__ == '__main__':
    main()