program nod;
uses crt;
var a,b,m,n,f:integer;
BEGIN
clrscr;
writeln('vvedi a b');
readln(a,b);
m:=a;n:=b;
while m<>n do
if m>n then m:=m-n
else n:=n-m;
f:=m;
writeln('HOD(', a,',', b,')=',f);
readln;
END.