uses crt;
var BH,CH,AH,BC,AB:real;
begin
    clrscr;
    write('Nhap BH: ');readln(BH);
    write('Nhap CH: ');readln(CH);
    while BH = 0 do
        begin
            write('Nhap BH: ');
            readln(BH);
        end;
    while CH = 0 do
        begin
            write('Nhap CH: ');
            readln(CH);
        end;
    BC:=BH+CH;
    AB:=sqrt(BC*BH);
    writeln('AB = ',AB:0:2);
    AH:=sqrt(BH*CH);
    writeln('Dien tich tam giac ABC: ',BC*AH/2:0:2);
readln;
end.

var BH,CH,AB,AC,BC,AH:real;
begin
repeat
write('Nhap BH: ');readln(BH);
write('Nhap CH: ');readln(CH);
if (BH < 1) then writeln('Nhap BH: (Yeu cau nhap lai BH > 0)');
if (CH < 1) then writeln('Nhap CH: (Yeu cau nhap lai CH > 0)');
until (BH > 0) and (CH > 0);
BC := BH+CH;
AB := sqrt(BC*BH);
AC := sqrt(BC*CH);
AH := sqrt(BH*CH);
writeln('AB = ',AB:0:2);
writeln('Dien tich tam giac ABC: ',(AH*BC)*1/2:0:2);
readln;
end.