#include <stdio.h>
#include <stdlib.h>
#ifndef EVAL
#define STDIO
#endif

typedef struct {
  int s, e;
} interval;

int N;

interval *I;
int *perm;

int *dominatedSet, dominatingNumber;

int cmp(const void* a, const void* b);
int length(interval i);
int overlap(interval A, interval B);

int main() {
  FILE *in, *out;

  int i, j;

#ifdef STDIO
  in = stdin;
  out = stdout;
#else
  in = fopen("input.txt", "r");
  out = fopen("output.txt", "w");
#endif  

  fscanf(in, " %d", &N);

  I = (interval*) calloc (N, sizeof(interval));
  dominatedSet = (int*) calloc (N, sizeof(int));
  perm = (int*) calloc (N, sizeof(int));
  for ( i = 0 ; i < N ; i++ ) {
    fscanf(in, " %d %d", &(I[i].s), &(I[i].e));
    dominatedSet[i] = 0;
    perm[i] = i;
  }

  qsort(perm, N, sizeof(int), cmp);
  
  dominatingNumber = 0;

  for ( i = 0 ; i < N ; i++ )
    if ( ! dominatedSet[ perm[i] ] ) {
      dominatedSet[ perm[i] ] = 2;
      dominatingNumber++;
    
      for ( j = 0 ; j < N ; j++ )
	if ( ! dominatedSet[ j ] && overlap(I[ perm[i] ], I[ j ]) )
	  dominatedSet[ j ] = 1;
    }


  fprintf(out, "%d\n", dominatingNumber);

  for ( i = 0 ; i < N ; i++ )
    if ( dominatedSet[ perm[i] ] == 2 )
      fprintf(stderr, "%d ", perm[i]);

  return 0;

}


int overlap(interval A, interval B) {
  if ( A.e < B.s || B.e < A.s )
    return 0;
  else
    return 1;
}

int cmp(const void* a, const void* b) {
  interval A = I[ * ((int*) a) ];
  interval B = I[ * ((int*) b) ];

  return length(B) - length(A);
}

int length(interval i) {
  return i.e - i.s + 1;
}