import math

H,W = map(int,input().split())

p_li = [0 for i in range(0,H)]

for y in range(0,H):
	p_li[y] = list(map(int,list(input())))

def calc(x0,y0):
	sum = 0
	for y in range(0,H):
		for x in range(0,W):
			if p_li[y][x] == 1:
				t = (x0 - x-1)**2.0 + (y0 - y-1)**2.0
				sum += math.sqrt(t) 
	return sum
	
ans = 10**20

	
for x in range(1,W+1):
	ans = min(ans,calc(x,0))
	ans = min(ans,calc(x,H+1))
	
for y in range(1,H+1):
	ans = min(ans,calc(0,y))
	ans = min(ans,calc(W+1,y))

	
print (ans)