program Project1;
{$APPTYPE CONSOLE}
uses
SysUtils;
const q:array[1..70]of real=(22,44,64.33,84.67,105,124,143,162,181,200,218,236,
254,272,290,308,326,344,362,380,392.13,404.25,
416.38,428.5,440.63,452.75,464.88,477,489.13,
501.25,513.38,525.5,537.63,549.75,561.88,574,
586.13,598.25,610.38,622.5,634.63,646.75,658.88,
671,683.13,695.25,707.38,719.5,731.63,743.75,
755.88,768,780.13,792.25,804.38,816.5,828.63,
840.75,852.88,865,863.5,862,860.5,859,857.5,856,854.5,853,
851.5,850);
function sum(a,b:integer):real;
var
r,m:real;
begin
if (a<59)and(a<>0) then m:=q[a] else
if (a>=59)and(a<>0)and(a<70) then m:=q[70] else
if (a>=70)and(a<>0) then m:=q[70]+((a-70)*15.71);
if (b<59)and(b<>0) then r:=q[b] else
if (b>=59)and(b<>0)and(b<70) then r:=q[70] else
if (b>=70)and(b<>0) then r:=q[70]+((b-70)*15.71);
if a<>0 then m:=m+10;
if b<>0 then r:=r+10;
sum:=m+r;
end;
var i,a,b,c:integer;min:real;
begin
assignfile(input,'d.in');reset(input);
read(a,b,c);
min:=sum(a+c*2,b);
for i:=1 to c*2 do
if (sum(a+c*2-i,b+i))<min
then min:=(sum(a+c*2-i,b+i));
assignfile(output,'d.out'); rewrite(output);
write(min:8:2);
Halt(0);
end.