program uocchunglonnhat;
uses crt;
var a,b,UCLN,n,m: integer;
begin
clrscr;
write(' nhap a='); readln(a);
write('nhap b='); readln(b);
m:=a;
n:=b;
while m<>n do begin
if m>n then
m:= m-n
else n:= n-m;
end;
writeln(' uoc chung lon nhat cua ',a,' va ',b,' laf: ',n);
readln
end.
