#include <iostream>

using namespace std;

int main()
{
    int n,m,s,s1,a[20][20],k=0;
    cin>>n>>m;
    for (int i=0;i<n;i++)
        for (int j=0;j<m;j++)
        cin>>a[i][j];
    for (int j=0;j<m;j++)
    {
        s=1;
           for (int i=0;i<n;i++){
            s=s*a[i][j];
           } k++;
        if(k==1)
        {
            s1=s;
        }
        if(s>s1)
        {
            s1=s;
        }


    }
    cout<<s1;

    return 0;
}