sr=input().split()
m=int(sr[0])
n=int(sr[1])
r=m%n
while(r!=0):
   m=n
   n=r
   r=m%n
print(n)
/**************************************************************
	Problem: 1335
	User: admin
	Language: Python
	Result: Accepted
	Time:100 ms
	Memory:34480 kb
****************************************************************/