#include <bits/stdc++.h>
using namespace std;
int n, q, a[(1 << 12 | 5)], loc[(1 << 12 | 5)], cnt;
int l[(1 << 16 | 5)], r[(1 << 16 | 5)], ans[(1 << 16 | 5)];
int ls[(1 << 12 | 5) << 2], rs[(1 << 12 | 5) << 2];
;
vector<vector<int> > id[(1 << 12 | 5) << 2];
vector<pair<int, int> > b[(1 << 12 | 5) << 4], fk;
void Merge(int first, int second) {
  fk.push_back(make_pair(first, second));
  cnt++;
}
int tot, root[(1 << 12 | 5)];
int qry(int first, int l, int r) {
  int L = lower_bound(b[first].begin(), b[first].end(), make_pair(l, 0)) -
          b[first].begin();
  int R = lower_bound(b[first].begin(), b[first].end(), make_pair(r + 1, 0)) -
          b[first].begin() - 1;
  if (L > R) return 0;
  return id[first][L][R];
}
void build(int &first, int l, int r, int st) {
  first = ++tot;
  assert(!l);
  if (l == r) {
    b[first].push_back(make_pair(loc[st + l], st + l));
    id[first].resize(1);
    id[first][0].resize(1);
    id[first][0][0] = loc[st + l];
    return;
  }
  int mid = (l + r) >> 1;
  build(ls[first], l, mid, st);
  build(rs[first], 0, r - mid - 1, st + mid + 1 - l);
  b[first].resize(r + 1);
  id[first].resize(r + 1);
  for (auto &i : id[first]) i.resize(r + 1);
  merge(b[ls[first]].begin(), b[ls[first]].end(), b[rs[first]].begin(),
        b[rs[first]].end(), b[first].begin());
  for (int i = l; i <= r; ++i)
    for (int j = i; j <= r; ++j) {
      int X = qry(ls[first], b[first][i].first, b[first][j].first),
          Y = qry(rs[first], b[first][i].first, b[first][j].first);
      if (X && Y) {
        Merge(X, Y);
        id[first][i][j] = cnt;
      } else if (X)
        id[first][i][j] = X;
      else if (Y)
        id[first][i][j] = Y;
    }
}
int main() {
  scanf("%d%d", &n, &q);
  for (int i = 1; i <= n; ++i) {
    scanf("%d", &a[i]);
    loc[a[i]] = i;
  }
  cnt = n;
  int B = min(n, (int)sqrt(q));
  int T = (n - 1) / B + 1;
  for (int i = 1; i <= T; ++i) {
    int l = (i - 1) * B + 1, r = min(n, i * B);
    build(root[i], 0, r - l, l);
  }
  for (int i = 1; i <= q; ++i) {
    scanf("%d%d", &l[i], &r[i]);
    int lst = 0;
    for (int j = 1; j <= T; ++j) {
      int ID = qry(root[j], l[i], r[i]);
      if (lst && ID) {
        Merge(lst, ID);
        lst = cnt;
      } else if (ID)
        lst = ID;
    }
    ans[i] = lst;
  }
  printf("%d\n", n + (int)fk.size());
  for (auto i : fk) printf("%d %d\n", i.first, i.second);
  for (int i = 1; i <= q; ++i) printf("%d ", ans[i]);
  return 0;
}
