#include <iostream>
#include <algorithm>
#include <cstdio>
#include <math.h>
using namespace std;
FILE*f=fopen("fact.in","r");
FILE*g=fopen("fact.out","w");
int main()
{
    int p,i;
    fscanf(f,"%d",&p);
    if(p<5)
        fprintf(g,"%d\n",5*p);
    else
    {
        for(p?i=5:i=6;p>0;i+=5)
        {
            int c=i;
            while(!(c%5))
            {
                --p;
                c/=5;
            }
        }
        if(p)
            fprintf(g,"-1");
        else
            fprintf(g,"%d\n",i-5);
    }
    return 0;
}