#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

struct BAR{
  int h, p, q;
  bool operator<(const BAR& rh)const{
    return h < rh.h;
  }
};

int main()
{
  int n, m, a;
  while (cin >> n >> m >> a && !(n == 0 && m == 0 && a == 0)){
    vector<BAR> v;
    for (int i = 0; i != m; ++i){
      BAR b;
      cin >> b.h >> b.p >> b.q;
      v.push_back(b);
    }

    sort (v.begin(), v.end());
    reverse(v.begin(), v.end());

    for (vector<BAR>::iterator it = v.begin();
	 it != v.end(); ++it){
      int p = it->p;
      int q = it->q;

      if (p == a){
	a = q;
      } else if (q == a){
	a = p;
      }
    }

    cout << a << endl;
  }
  
}