#include <bits/stdc++.h>
using namespace std;
```int main()


int n,oj;
cin >> n;

//    int i = 2 ;
int gs = 0;

for (int i = 2; i <= n; i ++ )
{
bool t = 1;
for (int j = 2; j * j <= i; j ++ )
{
if (i % j == 0)
{
t = 0;
break;
}
}
oj = i;
cout << i << oj  << endl;
if(t) gs ++ ;
}
cout << gs <<endl;

return 0;

}