#include <iostream>
#include <fstream>
using namespace std;
int nrz(int n)
{
    int nr=0;
    while(n)
    {
        nr+=n/5;
        n/=5;
    }
    return nr;
}
void cautare(int p,int &r)
{
    for(int i=28; i>=0; i--)
        if(nrz(r+(1<<i))<p)
            r+=(1<<i);
    r+=1;
}
int main()
{
    ifstream cin("fact.in");
    ofstream cout("fact.out");
    int p,r=0;
    cin>>p;
    cautare(p,r);
    if(nrz(r)==p)
        cout<<r;
    else
        cout<<"-1";
    return 0;
}