#include <cstdio>

using namespace std;

FILE * fin=fopen("fact.in","r");
FILE * fout=fopen("fact.out","w");
int getAparitii(int n)
{
    int ct=0;
    while (n%5==0){
        ct++;
        n/=5;
    }
    return ct;
}
int f(long long int n)
{
    if (n/5==0)
        return 0;
    else return n/5+f(n/5);
}
int main()
{
    int p;
    long long int n;
    fscanf(fin,"%d",&p);
    long long int a;
    if (p==0)
        fprintf(fout,"%d",1);
    else{
        a=5;
        while (f(a)<p)
            a+=5;
        if (f(a)==p)
            fprintf(fout,"%d",a);
        else
            fprintf(fout,"%d",-1);
    }
}