uses crt;
var dai,rong,cv,dt:real;
begin
clrscr;
repeat
write('Chieu dai='); readln(dai);
write('Chieu rong='); readln(rong);
until (dai>0) and (rong>0) and (dai>=rong);
cv:=(dai+rong)*2;
writeln('Chu vi=',cv:4:2);
dt:=dai*rong;
writeln('Dien tich=',dt:4:2);
readln;
end.