double a,b;
cin>>a;

if(a<=150)
a=150*0.4463;
if(a<=400)
a=150*0.4463+(a-150)*0.4663;
if(a>400)
a=150*0.4463+250*0.4663+(a-400)*0.5663;
cout<<fixed<<setprecision(1)<<a;
return 0;