/*
 * Solution Template for Buried Treasure
 * 
 * Australian Informatics Olympiad 2025
 * 
 * This file is provided to assist with reading of input and writing of output
 * for the problem. You may modify this file however you wish, or
 * you may choose not to use this file at all.
 */

#include <cstdio>

/* N is the number of clues. */
int N;
/* L is the number of locations. */
int L;

/*
 * A and B contain clues. Note that the arrays start from 0, and so the first
 * clue is (A[0], B[0]) and the last clue is (A[N-1], B[N-1]).
 */
int A[200005];
int B[200005];

int answer;
int main(void) {
  /* Read the values of N, L, and the clues. */
  scanf("%d%d", &N, &L);
  for (int i = 0; i < N; i++) {
    scanf("%d", &A[i]);
    scanf("%d", &B[i]);
  }

  /*
   * TODO: This is where you should compute your solution. Store the number of
   * locations that are consistent with all N clues into the variable answer.
   */

  /* Write the answer. */
  printf("%d\n", answer);

  return 0;
}