#include <iostream>
#include <vector>
#include <set>

int main(){
  while(true){
    int n, m, a;
    std::cin >> n >> m >> a;
    if(n == 0){break;}
    std::vector<std::pair<int, int> > crosses[2000];
    for(int i = 0; i < m; i++){
      int h, p, q;
      std::cin >> h >> p >> q;
      crosses[h].push_back(std::make_pair(p, q));
    }
    int current = a;
    for(int i = 1999; i >= 0; i--){
      for(int j = 0; j < crosses[i].size(); j++){
	int Q = -1;
	if(crosses[i][j].first == current){
	  Q = crosses[i][j].second;
	}else if(crosses[i][j].second == current){
	  Q = crosses[i][j].first;
	}
	if(Q == -1){continue;}
	current = Q;
	//std::cout << "current = " << current << std::endl;
	break;
      }
    }
    std::cout << current << std::endl;

  }
}