var
a,b,c:longint;     d:real;

begin
  readln(a,b,c);
  if (a=0) and (b=0) then d:=c div 2
  else
  if (a=100) and (b=0) then d:=c div 2+50
  else d:=c div 2+a div 5+b*0.3;
  writeln(d:0:0);
end.




/**************************************************************
	Problem: 1565
	User: admin
	Language: Pascal
	Result: Wrong Answer
****************************************************************/