#include <fstream>
#include <climits>
using namespace std;
int zero(int n)
{
    int x;
    int k=0,y;
    for(x=5;x<=n;x=x++)
    {
        y=x;
        while(y%5==0)
        {
            k++;
            y=y/5;
        }
    }
    return k;
}
int main()
{
    ifstream f("fact.in");
    ofstream g("fact.out");
    int N,P,ok;
    f>>P;
    N=1;
    ok=0;
    while(N<INT_MAX)
    {
       if(zero(N)==P)
       {
           ok=1;
           g<<N;
           break;
       }
        N++;
    }
    if(ok==0)
    g<<-1;
    return 0;
}