#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(){ float a,s; cin>>a; if(a>2 && a<10){ s=6+(a-2)*1.8; } else if(a>10){ s=6+(a-2)*1.8+(a-10)*(1.8+0.9); } cout<<s; }