#include <fstream>

using namespace std;
ifstream fin("fact.in");
ofstream fout("fact.out");
long long p, n, k, x;
int main()
{
    fin>>p;
    if (p==0) n=1;
    else{
    k=1;n=5;
    while (k<p)
    {  n=n+5;
        x=n;
        while(x%25==0)
        {k=k+2;
        x=x/25;

        }
        while(x%5==0)
        {k=k+1;
        x=x/5;

        }
    }}
    if (k==p)
    fout<<n;
    else
    fout<<-1;
     return 0;
}