import sys
input = sys.stdin.readline

H,W=map(int,input().split())
S=[input().strip() for i in range(H)]

ANS=1<<60

for i in range(H):
    x=-1
    y=i

    score=0
    for j in range(H):
        for k in range(W):
            if S[j][k]=='1':
                score+=((x-j)**2+(y-k)**2)**0.5
    ANS=min(ANS,score)

    x=W
    y=i
    score=0
    for j in range(H):
        for k in range(W):
            if S[j][k]=='1':
                score+=((x-j)**2+(y-k)**2)**0.5
    ANS=min(ANS,score)

for i in range(W):
    x=i
    y=-1

    score=0
    for j in range(H):
        for k in range(W):
            if S[j][k]=='1':
                score+=((x-j)**2+(y-k)**2)**0.5
    ANS=min(ANS,score)

    x=i
    y=H
    score=0
    for j in range(H):
        for k in range(W):
            if S[j][k]=='1':
                score+=((x-j)**2+(y-k)**2)**0.5
    ANS=min(ANS,score)

print(ANS)