#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 lu; cin>>lu; if(lu<=2){ cout<<"6"; } else if(lu>2&&lu<=10){ cout<<(lu-2)*1.8+6; } else if(lu>10){ cout<<(lu-2)*1.8+(lu-10)*[1.8+(1.8*1.5)]+6; } return 0; }