#include <bits/stdc++.h>
using namespace std;
const int B = 256;
int n, q, tree[555][266][266], val[22][266][266], pos[4444], a[4444], cnt, cpt,
    cur;
int arr[22][266], len[22], l, r, res[222222], ll, rr;
int ar[666], br[666], cr[666], la, lb, lc;
pair<int, int> ans[2222222];
char prt[55555555];
void merge(int l, int mid, int r, int node) {
  la = lb = lc = 0;
  for (int i = l; i <= mid; i++) ar[++la] = pos[i];
  for (int i = mid + 1; i <= r; i++) br[++lb] = pos[i];
  for (int i = l; i <= r; i++) cr[++lc] = pos[i];
  sort(ar + 1, ar + la + 1);
  sort(br + 1, br + lb + 1);
  sort(cr + 1, cr + lc + 1);
  for (int i = 1; i <= lc; i++) {
    for (int j = i; j <= lc; j++) {
      l = lower_bound(ar + 1, ar + la + 1, cr[i]) - ar;
      r = lower_bound(ar + 1, ar + la + 1, cr[j] + 1) - ar - 1;
      ll = lower_bound(br + 1, br + lb + 1, cr[i]) - br;
      rr = lower_bound(br + 1, br + lb + 1, cr[j] + 1) - br - 1;
      if (l > r)
        tree[node][i][j] = tree[(node << 1) | 1][ll][rr];
      else if (ll > rr)
        tree[node][i][j] = tree[node << 1][l][r];
      else {
        ++cnt;
        ans[cnt] =
            make_pair(tree[node << 1][l][r], tree[(node << 1) | 1][ll][rr]);
        tree[node][i][j] = cnt;
      }
    }
  }
}
void solve(int l, int r, int node) {
  if (l == r) {
    tree[node][1][1] = pos[l];
    return;
  }
  int mid = (l + r) >> 1;
  solve(l, mid, node << 1);
  solve(mid + 1, r, (node << 1) | 1);
  merge(l, mid, r, node);
}
void print(int x) {
  if (!x) {
    prt[cpt++] = '0';
    return;
  }
  while (x) {
    prt[cpt++] = '0' + (x % 10);
    x /= 10;
  }
}
int main() {
  scanf("%d%d", &n, &q);
  for (int i = 1; i <= n; i++) scanf("%d", &a[i]);
  for (int i = 1; i <= n; i++) pos[a[i]] = i;
  cnt = n;
  for (int i = 0; i * B + 1 <= n; i++) {
    for (int j = i * B + 1; j <= min(n, (i + 1) * B); j++) {
      arr[i][++len[i]] = pos[j];
    }
    sort(arr[i] + 1, arr[i] + len[i] + 1);
    solve(i * B + 1, min(n, (i + 1) * B), 1);
    for (int j = 1; j <= len[i]; j++) {
      for (int k = j; k <= len[i]; k++) val[i][j][k] = tree[1][j][k];
    }
  }
  for (int i = 1; i <= q; i++) {
    scanf("%d%d", &l, &r);
    cur = -1;
    for (int j = 0; j <= (n - 1) / B; j++) {
      ll = lower_bound(arr[j] + 1, arr[j] + len[j] + 1, l) - arr[j];
      rr = lower_bound(arr[j] + 1, arr[j] + len[j] + 1, r + 1) - arr[j] - 1;
      if (ll > rr) continue;
      if (cur == -1)
        cur = val[j][ll][rr];
      else {
        ++cnt;
        ans[cnt] = make_pair(cur, val[j][ll][rr]);
        cur = cnt;
      }
    }
    res[i] = cur;
  }
  cpt = 1;
  prt[0] = '\n';
  for (int i = q; i >= 1; i--) {
    print(res[i]);
    if (i > 1) prt[cpt++] = ' ';
  }
  prt[cpt++] = '\n';
  for (int i = cnt; i > n; i--) {
    print(ans[i].second);
    prt[cpt++] = ' ';
    print(ans[i].first);
    prt[cpt++] = '\n';
  }
  print(cnt);
  reverse(prt, prt + cpt);
  fwrite(prt, 1, cpt, stdout);
  return 0;
}
