var a,b,r:longint;
    f:text;
begin
assign(f,'euclid2.in'); reset(f);
readln(f,a,b);
close(f);
r:=a mod b;
while r>0 do
begin
a:=b;
b:=r;
r:=a mod b;
end;
assign(f,'euclid2.out'); rewrite(f);
writeln(f,b);
close(f);
end.