#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ double x,y; cin>>x; if(x<=2) { y=6; } else if(2<x<=10) { y=1.8*x+2.4; } if(x>10) { y=2.7*x-6.6; } printf("%.1lf",y); return 0; }