#include <iostream>
#include <cmath>
using namespace std;
int main()
{ int n, ok = 1, radical; cin >> n; int nr = n;
while( ok )
{   ++nr; bool ok1 = 0;
    radical = sqrt(nr);
    for( int i = 2; i <= radical; ++i)
    {
        if(!(nr % i))
        {
            ok1 = 1;
        }
    }
    if(ok1==0)
        ok = 0;
}
    cout << nr;

    return 0;
}