#include<bits/stdc++.h> using namespace std; int main(){ double a; cin>>a; if(a<=150){ printf("%.1lf",0.4463a); }if(a<=400 and a>150){ printf("%.1lf",0.4663(a-150)+0.4463150); }if(a>400){ printf("%.1lf",0.5663(a-400)+0.4463150+0.4663250); } return 0; }