#include<iostream>
using namespace std;
int main()
{
int n, m;
cin >> n >> m;
int a[n][m];
int answer = 1;
for (int i = 0; i < n; i++)
for (int j = 0; j < m; j++)
cin >> a[i][j];
if (a[i][j] > 0)
answer *= a[i][j];
}
cout << answer;
#include<iostream>
using namespace std;
int main()
{
int n, m;
cin >> n >> m;
int a[n][m];
int answer = 1;
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
cin >> a[i][j];
if (a[i][j] > 0)
{
answer *= a[i][j];
}
}
}
cout << answer;
}