#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 a,b=0; cin>>a; if(a<=2) { b+=6; } else if(a<=10) { b=6+(a-2)*1.8; } else { b=6+8*1.8+(a-10)*1.8*(1.5); } cout<<b; return 0; }