#include <fstream>
using namespace std;
int main()
{
    int n=0,p,i,j;
    ifstream in ("fact.in");
    ofstream out("fact.out");
    in>>p;
    if (p>0)
    {
        for (i=5;i<=p*5;i+=5)
            if((n+=i/5)==p) break;
        out<<i;
    }
    out<<1;
    return 0;
}