#include <bits/stdc++.h>
using namespace std;
const int B = 1 << 8, N = (1 << 12) | 5;
int t[B * 2][B | 5][B | 5];
int tt[20][B | 5][B | 5];
int n, Q, a[N], pos[N], ans[N * B];
int ansL[1 << 22], ansR[1 << 22], nd;
int p1[N], p2[N], q[N], p[20][N];
int ADD(int x, int y) {
  if (!x || !y) return x + y;
  ansL[++nd] = x;
  ansR[nd] = y;
  return nd;
}
void output() {
  printf("%d\n", nd);
  for (int i = (int)(n + 1); i <= (int)(nd); i++)
    printf("%d %d\n", ansL[i], ansR[i]);
}
void init(int k, int L, int R) {
  if (L == R) {
    t[k][1][1] = pos[L];
    return;
  }
  int mid = (L + R) / 2;
  init(k * 2, L, mid);
  init(k * 2 + 1, mid + 1, R);
  memset(p1, 0, sizeof(p1));
  memset(p2, 0, sizeof(p2));
  for (int i = (int)(L); i <= (int)(mid); i++) p1[pos[i]]++;
  for (int i = (int)(mid + 1); i <= (int)(R); i++) p2[pos[i]]++;
  for (int i = (int)(1); i <= (int)(n); i++) {
    p1[i] += p1[i - 1];
    p2[i] += p2[i - 1];
  }
  *q = 0;
  for (int i = (int)(L); i <= (int)(R); i++) q[++*q] = pos[i];
  sort(q + 1, q + *q + 1);
  for (int i = (int)(1); i <= (int)(*q); i++)
    for (int j = (int)(i); j <= (int)(*q); j++) {
      int pl1 = p1[q[i] - 1] + 1, pr1 = p1[q[j]];
      int pl2 = p2[q[i] - 1] + 1, pr2 = p2[q[j]];
      int v1 = (pl1 <= pr1 ? t[k * 2][pl1][pr1] : 0);
      int v2 = (pl2 <= pr2 ? t[k * 2 + 1][pl2][pr2] : 0);
      t[k][i][j] = ADD(v1, v2);
    }
}
int main() {
  scanf("%d%d", &n, &Q);
  for (int i = (int)(1); i <= (int)(n); i++) scanf("%d", &a[i]), pos[a[i]] = i;
  int cnt = (n - 1) / B + 1;
  nd = n;
  for (int i = (int)(1); i <= (int)(cnt); i++) {
    int L = (i - 1) * B + 1, R = min(n, i * B);
    for (int j = (int)(L); j <= (int)(R); j++) p[i][pos[j]] = 1;
    for (int j = (int)(1); j <= (int)(n); j++) p[i][j] += p[i][j - 1];
    init(1, L, R);
    int sum = R - L + 1;
    for (int j = (int)(1); j <= (int)(sum); j++)
      for (int k = (int)(j); k <= (int)(sum); k++) tt[i][j][k] = t[1][j][k];
  }
  for (int i = (int)(1); i <= (int)(Q); i++) {
    int l, r;
    scanf("%d%d", &l, &r);
    ans[i] = 0;
    for (int j = (int)(1); j <= (int)(cnt); j++) {
      int pl = p[j][l - 1] + 1;
      int pr = p[j][r];
      ans[i] = ADD(ans[i], tt[j][pl][pr]);
    }
  }
  output();
  for (int i = (int)(1); i <= (int)(Q); i++) printf("%d ", ans[i]);
}
