program tinh_dien_tich;
uses crt;
var a,b,c,s,p:real;
begin
write('Nhap canh 1 = '); read(a);
write('Nhap canh 2 = '); read(b);
write('Nhap canh 3 = '); read(c);
p:=1/2*(a+b+c);
s:= SQRT(p*(p-a)*(p-b)*(p-c));
writeln('Dien tich tam giac là: ',s:2:2);
readln;
end.