from math import sqrt
def f(p,X):
    a,b=p
    S=0
    for x,y in X:
        S+=sqrt((x-a)**2+(y-b)**2)
    return S

H,W=map(int,input().split())
X=[]
for i in range(1,H+1):
    P=input()
    for j in range(1,W+1):
        if P[j-1]=="1":
            X.append((i,j))

Ans=float("inf")
for j in range(1,W+1):
    Ans=min(Ans,f((0,j),X),f((H+1,j),X))

for i in range(1,H+1):
    Ans=min(Ans,f((i,0),X),f((i,W+1),X))

print(Ans)