x,y= map(int,input().split())
i=min(x,y)
while i>0:
 if x%i==0 and y%i==0 :
  print(i)
  break
 else:
  i=i-1

重發打錯
x,y= map(int,input().split())
i=min(x,y)
z=max(x,y)
while Z%i!=0:
 x=i
 y=z%i
 i=min(x,y)
 z=max(x,y)
print('i')

又打錯
x,y= map(int,input().split())
i=min(x,y)
z=max(x,y)
while Z%i!==0:
 x=i
 y=z%i
 i=min(x,y)
 z=max(x,y)
print('i')

抱歉一直打錯
x,y= map(int,input().split())
i=min(x,y)
z=max(x,y)
while z%i!=0:
 x=i
 y=z%i
 i=min(x,y)
 z=max(x,y)
print(i)