Uses crt;
Var a, b, c ,d:integer;
Begin clrscr ;
Write('nhap a, b, c,d'); readln(a,b,c,d);
If a <18 then write('LA Thieu nien ');
If b >= 18
Else b<=39 then write('LA Thanh nien ');
If c>=40
Else c<=60 then write ('LA thing nien ');
If d >60 then write ('LA Lao nien ');
Readln;
End.