#include <bits/stdc++.h> using namespace std; int a; int b; int main() { cin>>b; if (b>400) a=150*0.4463+250*0.4663+(b-400)*0.5663; if (b>150) a=150*0.4463+(b-150)*0.4663; if (b<=150) a=b*0.4463; cout<<floor(a*10+0.5)/10.0<<endl; return 0; }