def gcd(a,b):
    if a>b:
        m=a
        t=b
    else:
        m=b
        t=a
    r=m%t
    while r!=0:
        m=t
        t=r
        r=m%t
    return t
A,B=(int(i) for i in input (). split ())
print (gcd(A,B))