H,W = map(int, input().split())
def dist(a,b,x,y):
    return ((a-x)**2+(b-y)**2)**0.5
pos = {}
for i in range(1,H+1):
    pos[(i,0)] = 0
    pos[(i,W+1)] = 0
for j in range(1,W+1):
    pos[(0,j)] = 0
    pos[(H+1,j)] = 0
for i in range(H):
    s = input()
    for j in range(W):
        if s[j]=="1":
            for y,x in pos:
                pos[(y,x)] += dist(i+1,j+1,y,x)
ans = 10**10
for y,x in pos:
    ans = min(ans,pos[(y,x)])
print(ans)