{ This is the example given in the Dragon book }
program example;

var x, y: integer;


function gcd(a,b: integer): integer;
begin
    if b = 0 then gcd := a
    else gcd := gcd(b, a mod b)
end;

begin
    x := readinteger;
    y := readinteger;
    writeinteger(gcd(x, y))
end.