var a,b:integer;
f:text;
begin
assign(f,'cmmdc.in');reset(f);read(f,a);read(f,b);close(f);
assign(f,'cmmdc.out');rewrite(f);
while a<>b do
      if a>b then a:=a-b
             else b:=b-a;
if a<>1 then write(f,a) else write(f,0); close(f); end.