program  s_tam_giac;
uses crt;
Var
a, b, c: Integer;
p, s: Real;
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);
p := (1/2)*(a+b+c);
s := Sqrt (p*(p - a)*(p - b)*(p - c));
Writeln ('Dien tich tam giac = ', s:10:2);
Readln;
End.