n,m=list(map(int,input().split()))
a=list()
b=list()
for i in range(n):
    a.append(list(map(int,input().split())))
for i in range(n):
    b.append(list(map(int,input().split())))
sum=0

for i in range(n):
    for j in range(m):
        if a[i][j]==b[i][j]:
            sum=sum+1
print("%.2lf"%(100*sum/(n*m)))


/**************************************************************
	Problem: 1407
	User: admin
	Language: Python
	Result: Accepted
	Time:178 ms
	Memory:34480 kb
****************************************************************/