#include <iostream>

using namespace std;

int _tmain(int argc, _TCHAR* argv[])
{
	int mas[99][99];
	int x, y, sum=0, r=0;
	cin >> x >> y;
	for (int i = 0; i < x; i++)
		for (int j = 0; j <y; j++){
			cin >> mas[i][j];
			sum +=mas[i][j];
			r++;
		}
		cout << sum/r;
	return 0;
}