#include <iostream>
#include <iomanip>
using namespace std;
 
int main() {
    int n, m;
    cin >> n >> m;
     
    int same_count = 0;
    int total = n * m;
     
    // 存储第一幅图像
    int** image1 = new int*[n];
    for (int i = 0; i < n; ++i) {
        image1[i] = new int[m];
        for (int j = 0; j < m; ++j) {
            cin >> image1[i][j];
        }
    }
     
    // 读取并比较第二幅图像
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < m; ++j) {
            int pixel2;
            cin >> pixel2;
            if (image1[i][j] == pixel2) {
                same_count++;
            }
        }
    }
     
    // 释放内存
    for (int i = 0; i < n; ++i) {
        delete[] image1[i];
    }
    delete[] image1;
     
    // 计算相似度百分比
    double similarity = (double)same_count / total * 100;
     
    // 输出结果，保留两位小数
    cout << fixed << setprecision(2) << similarity << endl;
     
    return 0;
}
 
/**************************************************************
	Problem: 1407
	User: fuyijun
	Language: C
	Result: Compile Error
****************************************************************/