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