#include <stdio.h>
int retnr(int n)
{
    if(n<5)
        return n*5;
    if(n==5)
        return -1;
    int k=5,z=6,descaz=1;
    while(k!=n)
    {
        if(k+z==n)
            return -1;
        if(k+z<n)
        {
            k=k+z;
            descaz++;
        }
        else
            return (n-descaz)*5;
    }

}
int main()
{
    int n;
    FILE *f=fopen("fact.in","r");
    fscanf(f,"%d",&n);
    fclose(f);
    FILE *g=fopen("fact.out","w");
    if(n==0)
    {
        fprintf(g,"1");
        return 0;
    }
    fprintf(g,"%d",retnr(n));
    return 0;
}