import java.io.*;
import java.util.*;

class B {
	public static void main(String[] args) throws Exception {
		Scanner cin = new Scanner(System.in);

		while(true) {
			int n = cin.nextInt();
			int m = cin.nextInt();
			int a = cin.nextInt();

			if(n == 0 && m == 0 && a == 0) { break; }

			Swapper[] s = new Swapper[m];

			for(int i = 0; i < m; i++) {
				int y = cin.nextInt();
				int u = cin.nextInt();
				int v = cin.nextInt();
				s[i] = new Swapper(u, v, y);
			}

			Arrays.sort(s);

			for(int i = m - 1; i >= 0; i--) { a = s[i].move(a); }
			System.out.println(a);
		}
	}

	private static class Swapper implements Comparable<Swapper> {
		private int u, v, y;

		public Swapper(int u, int v, int y) {
			this.u = u;
			this.v = v;
			this.y = y;
		}

		public int compareTo(Swapper that) {
			if(this.y != that.y) { return this.y - that.y; }
			if(this.u != that.u) { return this.u - that.u; }
			if(this.v != that.v) { return this.v - that.v; }
			return 0;
		}

		public int move(int a) {
			if(a == u || a == v) return a ^ u ^ v;
			return a;
		}
	}
}