#include <iostream>
#include <fstream>
using namespace std;
FILE *fin=fopen("fact.in", "r");
FILE *fout=fopen("fact.out", "w");
int main()
{
    int P, x, y;
    fscanf(fin, "%d", &P);
    x=0;
    if(P==0) fprintf(fout, "1");
    else{
    while(P>0)
    {
        x=x+5;
        y=x;
        P--;
        y=y/5;
        while(y%5==0)
        {
            y=y/5;
            P--;
        }
    }
    if(P<0) fprintf(fout, "%d", -1);
    else fprintf(fout, "%d", x);
    }
    return 0;
}