#include <fstream>

using namespace std;

ifstream fin("fact.in");
ofstream fout("fact.out");

long long int ans,i,j,d,aux;
int n;

int main()
{
    fin>>n;
    for(i = 5 ; d < n ; i += 5 )
    {
        aux = i;

        while( aux % 5 == 0 )
        {
            ++d;
            aux /= 5;
        }
    }
    if( d == n)
        fout<<i-5;
    else
        fout<<"-1";

return 0;
}