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

class B {
	private static int YMAX = 1000;

	public static void main(String[] args) {
		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; }

			int[][] s = new int[n][YMAX+1];

			for(int i = 0; i < n; i++) {
				for(int j = 0; j <= YMAX; j++)
					s[i][j] = i;
			}

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

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