#include <cstdio>
#include <vector>
using namespace std;
typedef pair<int,int> e_t;
#define N 1002
int n,m,a;
vector<e_t> es[N];

int main()
{
  while(scanf("%d%d%d",&n,&m,&a),n|m|a) {
    for (int i=0;i<N;++i) es[i].clear();
    for (int i=0;i<m;++i) {
      int h,p,q;scanf("%d%d%d",&h,&p,&q);
      es[h].push_back(make_pair(p,q));
    }
    int c=a;
    for (int h=N-1;h>=0;--h) {
      for (int i=0;i<es[h].size();++i)
	if (es[h][i].first==c) {
	  c=es[h][i].second;
	  break;
	} else if (es[h][i].second==c){
	  c=es[h][i].first;
	  break;
	}
      //      printf("%d %d\n",h,c);
    }
    printf("%d\n",c);
  }
  
}