Uses Crt;
var
a,b,c,tg:real;
begin
Read(a,b,c);
tg:=sin(a-21)/cos(a-21);
Writeln((2*c+tg)/(b*c/a+1));
ReadKey
end.
--------------------------------------
uses Crt;
var
d,pi:real;
begin
pi:=3.14159;
Read(d);
Writeln(pi*d);
ReadKey
end.
---------------------------
uses Crt;
var
v1,v2,t1,t2:real;
begin
Read(v1,t1,v2,t2);
Writeln('V=',v1+v2,',T=',(v1*t1+v2*t2)/(v1+v2));
ReadKey
end.