/**
 *  Amida, the City of Miracle (Problem A, Practice Contest for Japan Domestic, 2006-06-18)
 *  by Kenji Inoue, 2007-01-05
 **/

#include <iostream>
#include <map>
#include <set>

using namespace std;

typedef multimap< int, pair<int, int> > HL; // horizontal line

int main() {
  int n, m, a;
  while (cin >> n >> m >> a, (n || m || a)) {
    HL hl;
    set<int> hs; // heights
    for (int i=0; i<m; i++) {
      int h, p, q;
      cin >> h >> p >> q;
      hl.insert( make_pair(h, make_pair(p, q)) );
      hs.insert(h);
    }

    int c = a; // current line
    for (set<int>::reverse_iterator sit = hs.rbegin(); sit != hs.rend(); sit++) {
      int h = *sit;
      for (HL::iterator it = hl.lower_bound(h); it != hl.upper_bound(h); it++) {
        pair<int, int> v = it->second;
        if (v.first == c) {
          c = v.second;
          break;
        } else if (v.second == c) {
          c = v.first;
          break;
        }
      }
    }

    cout << c << endl;
  }

  return 0;
}