const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;
void async function () {
// Write your code here
while(line = await readline()){
let str = line; //读取输入
let arr = str.split(" ").map(Number); //把输入变成数字数组
let n = arr[0]; //总节点数
let removeNum = arr[arr.length-1]; //要移除的节点
let unRemoveArr = []; //定义未移除节点的数组
unRemoveArr[0] = arr[1]; //第一个节点为数字数组下标为1的数字
for(let i = 0,j = 0;i < n-1; i++, j+=2){ //执行五次加入节点
let tempArr = arr.slice(2+j, 4+j); //截取节点开头和新加入的节点数字
let start = tempArr[1]; //节点开头
let newNum = tempArr[0]; //新加入的节点数字
let index = unRemoveArr.indexOf(start); //节点开头的下标
unRemoveArr.splice(index+1,0,newNum); //加入新数字
}
let RemovedArr = unRemoveArr.filter(item => item!=removeNum); //删除要移除的节点
console.log(RemovedArr.join(" ")) //输出
}
}()