#include<bits/stdc++.h>
using namespace std;
int n,m,i,j,s;
float a[101][101],zb;
int main(){
	cin>>n>>m;
	for(i=0;i<n*2;i++){
		for(j=0;j<m;j++){
			cin>>a[i][j];
		}
	}
	for(i=0;i<n;i++){
		for(j=0;j<m;j++){
			if(a[i][j]==a[i+n][j])  s++;
		}	
	}
	zb=s*1.00/(n*m)*100;
	printf("%.2f",zb);
	return 0;
}
/**************************************************************
	Problem: 1407
	User: zhangziang
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2116 kb
****************************************************************/