#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(){ int a; cin>>a; if(a<=2){ cout<<6; } if(a>=3&&a<=10){ cout<<6+1.8*(a-2); } if(a>=11){ cout<<6+2.7*(a-10)+14.4; } return 0; }