#include <stdio.h> int main() { int a; scanf ("%d",&a); if (a<=2){ printf("%d",6); } else if (a>2 && a<=10){ double t; t=6+1.8*(a-2); printf("%.1lf",t); } else{ double p; p=20.4+2.7*(a-10); printf("%.1lf",p); } return 0; }