#include <cstdio>
using namespace std;

int p_d_5(int n)
{
    for(int j=1;n>1;n/=5,j++)
    return(j-1);
}

int main()
{
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
    int p;
    scanf("%d",&p);
    if(p==0)
        printf("1");
    else
    {
        int i;
        for(i=1;i<=p;++i)
            if(!(i%5))
                i+=p_d_5(i);
        --i;
        if(p==i)
            printf("%d",5*i);
        else
            printf("-1");
    }
    return 0;
}