#include<iostream>
#include<cstdio>
#include<vector>
#include<string>
#include<cmath>
#include<algorithm>
#include<functional>
#include<queue>
#include<map>
#include<set>
#include<complex>
#include<sstream>
#include<iterator>
#include<cstdlib>
#include<bitset>

using namespace std;

int main()
{
  int n , m , a;
  while(cin >> n >> m >> a && (n||m||a))
    {
      int dat[n] ; 
      for(int i = 0 ; i < n ; i++)
	dat[i] = i;
      vector<pair<int,pair<int,int> > >yoko(m);
      for(int i = 0 ; i < m ; i++)
	{
	  int h , p , q;
	  cin >> h >> p >> q;
	  yoko[i] = make_pair(h , make_pair(p-1 , q-1));
	}
      sort(yoko.begin() , yoko.end() , greater<pair<int,pair<int,int> > >());
      for(int i = 0 ; i < m ; i++)
	{
	  swap(dat[yoko[i].second.first] , dat[yoko[i].second.second]);
	}
      int idx = find(dat , dat + n, a-1) - dat;
      cout << idx + 1 << endl;
    }
  return 0;
}