program baitap;
var s,a,b,c,aa,bb,cc:real;
procedure nhap;
begin
write('nhap 3 canh tam giac thu nhat :a,b,c=');
readln(a,b,c);
write('nhap 3 canh tam giac thu hai:aa,bb,cc=');
readln(aa,bb,cc);
end;
function dientich(x,y,z:real):real;
var ncv:real;
begin
ncv:=(x+y+z)/2;
dientich:=sqrt(ncv*(ncv-a)*(ncv-b)*(ncv-c));
end;
procedure tinhdt;
begin
s:=0;
s:=s+dientich(a,b,c);
s:=s+dientich(aa,bb,cc);
end;
procedure xuat;
begin
writeln('tong dien tich hai tam giac la :',s:10:5);
readln;
end;
begin
nhap;
tinhdt;
xuat;
end.