#include<stdio.h>
using namespace std;
int p,x;
int main(){
    freopen("fact.in","r",stdin);
    freopen("fact.out","w",stdout);
    scanf("%d", &p);
    if((p+1)%6==0)
        printf("-1");
        else{
            x=p*5-(p/6)*5;
            printf("%d" ,x);
        }
    fclose(stdin);
    fclose(stdout);
    return 0;
}