N=input()
name2=[input().split() for i in range(N)]
name1=[]

for i in range(N):
    name1.append(name2[i])
    del name2[i]

ans=[]
for j in name2:
    if j in name1:
        continue
    else:
        ans.append(j)
    
for k in ans:
    print(k)