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

#include <iostream>

using namespace std;

struct HL {
  int h, p, q;
} hl[1001];

int main() {
  int n, m, a;
  while (cin >> n >> m >> a, (n || m || a)) {
    memset(hl, 0, sizeof(hl));
    for (int i=0; i<m; i++) {
      cin >> hl[i].h >> hl[i].p >> hl[i].q;
    }

    int c = a; // current line
    for (int h=1000; h>0; h--) {
      for (int i=0; i<m; i++) {
        if (hl[i].h != h) { continue; }

        if (hl[i].p == c) {
          c = hl[i].q;
          break;
        } else if (hl[i].q == c) {
          c = hl[i].p;
          break;
        }
      }
    }

    cout << c << endl;
  }

  return 0;
}