#include <iostream>
#include <fstream>
using namespace std;
ifstream in("fact.in");
ofstream out("fact.out");
long long p, i, cate=0, j;
int ok;
int main()
{
    in>>p;
    if(p==0)
    {
        out<<1;
    }
    else
    {
        ok=0;
        for(i=5; ok==0; i=i+5)
        {
            j=i;
            while(j%5==0)
            {
                ++cate;
                j/=5;
            }
            if(cate>p)
                ok=2;
            if(p==cate)
                ok=1;
        }
        if(ok==2)
            out<<-1;
        else
            out<<i-5;
    }
    return 0;
}