uses crt;
var a,b,c:real;
{----------------------------chuong-trinh-con-----------------------------}
function tong(x,y:real):real;
begin
tong:=x+y;
end;
{----------------------------chuong-trinh-chinh---------------------------}
begin
clrscr;
write('a='); readln(a);
write('b='); readln(b);
write('c='); readln(c);
writeln('Tong cua ba so la: ',tong(a,tong(b,c)):4:2);
readln;
end.