program dien_tich;
uses crt;
var a,b,c:integer;
{---Dien-tich---}
function S(a,b,c:integer):real;
var P:real;
begin
P:=(a+b+c)/2;
S:=sqrt(P*(P-a)*(P-b)*(P-c));
end;
{---CT-Chinh---}
BEGIN
clrscr;
write('Nhap do dai canh thu nhat: '); readln(a);
write('Nhap do dai canh thu hai: '); readln(b);
write('Nhap do dai canh thu ba: '); readln(c);
writeln('Dien tich tam giac la: ',S(a,b,c));
readln;
end.