#include <iostream>
#include <vector>

using namespace std;

struct bar_t {
  int s1, s2, h;
  const bool operator<(const bar_t &o) const {
    return h > o.h;
  }
};

int main()
{
  int n, m, a;

  while(cin >> n >> m >> a) {
    if (n == 0 && m == 0 && a == 0) { break; }

    vector<bar_t> bars;
    for (int i = 0; i < m; i++) {
      bar_t input;
      cin >> input.h >> input.s1 >> input.s2;
      bars.push_back(input);
    }
    sort(bars.begin(), bars.end());

    for (vector<bar_t>::iterator p = bars.begin(); p != bars.end(); p++) {
      if (p->s1 == a) { a = p->s2; }
      else if (p->s2 == a) { a = p->s1; }
    }
    cout << a << endl;
  }
  return 0;
}