#include<bits/stdc++.h> using namespace std; int main(){ int n; cin>>n; if(0<=n&&n<=10) cout<<6*n; else if(11<=n&&n<=20) cout<<60+2*(n-10); else if(21<=n&&n<=40) cout<<80+1*(n-20); else if(40==n) cout<<"100"; return 0; }