UCLN

uses crt;
var u,v:integer;
begin
    clrscr;
    write('Nhap u,v: ');
    readln(u,v);
    while u<>v do
        if u>v then
            u:=u-v
        else
            v:=v-u;
    write('UCLN= ',u);
    readln
end.