#include <iostream>
#include <vector>

using namespace std;

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

  while(cin >> n >> m >> a && n && m && a) {
    int g[1001][101] = {0};

    for (int i = 0; i < m; i++) {
      int h, p, q;
      cin >> h >> p >> q;
      g[h][p] = q;
      g[h][q] = p;
    }

    int now = a;
    for (int i = 1000; i > 0; i--) {
      if (g[i][now]) {
	now = g[i][now];
      }
    }

    cout << now << endl;
  }

  return 0;
}