#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<ctype.h>
#include<iostream>

using namespace std;
typedef struct {
	int h, p, q;
} H;

H line[1000];

// 123456...
int cmp( const void *p1, const void *p2 )
{
	H *pp1 = (H*)p1;
	H *pp2 = (H*)p2;
	if( pp1->h > pp2->h )
		return -1;
	if( pp1->h < pp2->h )
		return 1;
	return 0;
}

int main(void)
{
	while(1){
		int n,m,a;
		scanf( "%d%d%d", &n, &m, &a );
		if( n == 0 && m == 0 && a == 0 )
			break;

		for( int i = 0; i < m; i ++ ){
			scanf( "%d%d%d", &line[i].h, &line[i].p, &line[i].q );
		}
		
		qsort( line, m, sizeof(H), cmp );

		for( int i = 0; i < m; i ++ ){
			if( line[i].p == a )
				a = line[i].q;
			else if( line[i].q == a )
				a = line[i].p;
		}
		printf( "%d\n", a );
	}
	return 0;
}