#include <iostream>
#include <fstream>
using namespace std;
int nz(int n)
{
    int nr=0,i,x;
    for(i=5;i<=n;i+=5)
    {
        x=i;
        while(x%5==0 and x!=0)
        {
            nr++;
            x/=5;
        }
    }
    return nr;
}
int main()
{
    int k,i=0;
    ifstream f("fact.in");
    ofstream g("fact.out");
    f>>k;
    if(k==0)
        g<<1;
    else
    {
        while(nz(i)<k)
        i++;
    if(nz(i)==k)
        g<<i;
        else
            g<<-1;
    }
    return 0;
}