v= map(chr, range(65, 91))
 
i=0
j=0
c=[]
while i < 8:
	x,y= raw_input().split(" ")
	if x<y:		
		c+=[v[j+1]]		
	else:
		c+=[v[j]]	
	j+=2			
	i+=1
 
i=0
j=0
v=[]
while i < 4:
	x,y= raw_input().split(" ")
	if x<y:		
		v+=[c[j+1]]
	else:
		v+=[c[j]]	
	j+=2
	i+=1
 
i=0
j=0
c=[]
 
while i < 2:
	x,y= raw_input().split(" ")
	if x<y:		
		c+=[v[j+1]]		
	else:
		c+=[v[j]]
	j+=2			
	i+=1
 
x,y= raw_input().split(" ")
 
if x<y:
	print c[1]
 
else:
	print c[0]
 
 

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

NCAxCjEgMAowIDQKMyAxCjIgMwoxIDIKMiAwCjAgMgoxIDIKNCAzCjAgMQozIDIKMyA0CjEgNAoxIDA=

4 1
1 0
0 4
3 1
2 3
1 2
2 0
0 2
1 2
4 3
0 1
3 2
3 4
1 4
1 0