#include <iostream>
#include <fstream>
using namespace std;

int main()
{
    ifstream fin("factorial.in");
    ofstream fout("factorial.out");
    int l=0, i, n=1, k=1, cn, p, c=0;
    fin>>p;
    while(c==0){
        l=0;
        i=0;
        k=k*n;
        n++;
        cn=k;
        while(cn>0){
            if(cn%10==0){
                l++;
            }
            if(l>0 && cn%10>0){
                i++;
            }
            cn/=cn;
        }
        if(i==p){
            c++;
        }
    }
    fout<<n;
    return 0;
}