#include <stdio.h>
#include <stdlib.h>

int
main (void)
{
  int n, m, a, i;
  scanf ("%d%d%d", &n, &m, &a);
  int *data[1000];
  data[0] = (int *) calloc (sizeof (int), 1001 * n);
  for (i = 1; i < 1000; i++)
    data[i] = data[0] + n * i;
  while (1)
    {
      int h, from, to;
      scanf ("%d%d%d", &h, &from, &to);
      if ((h | from | to) == 0)
	break;
      data[h - 1][from - 1] = to;
      data[h - 1][to - 1] = from;
    }
  for (i = 1000; i > 0; i--)
    {
      if (data[i - 1][a - 1] == 0)
	continue;
      a = data[i - 1][a - 1];
    }
  free (data[0]);
  printf ("%d\n", a);
  return 0;
}