#include <stdio.h>

using namespace std;

void caut(int p)
{
    int k=0;
    long long i,x;
    for(i=1;k<p;i++)
        if(i%5==0)
    {
        x=i;
        while(x%5==0)
        {
            k++;
            x=x/5;
        }
    }
    if(k==p)
        printf("%lld",i-1);
    else
        printf("-1");
}

int main()
{
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
    int p;
    scanf("%d",&p);
    caut(p);
}