n=input().split()
a=int(n[0])
head=int(n[1])
key=int(n[2])
m=[[0 for i in range(0,2)] for j in range(0,a+1)]
for i in range(0,a):
    x=input().split()
    m[i][0]=int(x[0])
    m[i][1]=int(x[1])
flag=0
if key<m[head][0]:
    print(key,end=' ')
    flag=1
while head!=-1:
    print(m[head][0],end=' ')
    if key>=m[head][0] and key<=m[m[head][1]][0] and flag==0:
        print(key,end=' ')
        flag=1
    head=m[head][1]
if flag==0:
    print(key)

偷懒链表