#include <bits/stdc++.h>
using namespace std;
using lint = long long;
using ulint = unsigned long long;
const int N = 1500 + 1;
int a[N];
int bit[N];
int back[N];
int lsb(int x) { return x & -x; }
int query(int r) {
  int res = 0;
  for (; r > 0; r -= lsb(r)) {
    res = max(res, bit[r]);
  }
  return res;
}
void update(int r, int k, int id) {
  for (; r < N; r += lsb(r)) {
    if (k > bit[r]) {
      bit[r] = k;
      back[r] = id;
    }
  }
}
int main(void) {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int n;
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
    a[i] += a[i - 1];
  }
  map<int, vector<pair<int, int>>> sums;
  for (int l = 1; l <= n; l++) {
    for (int r = l; r <= n; r++) {
      sums[a[r] - a[l - 1]].emplace_back(l, r);
    }
  }
  int best = -1, best_sum = -1;
  for (auto &sum : sums) {
    fill(begin(bit), end(bit), 0);
    auto &vec = sum.second;
    for (int i = 0; i < vec.size(); i++) {
      auto [l, r] = vec[i];
      update(r, query(l - 1) + 1, i);
    }
    if (query(n) > best) {
      best = query(n);
      best_sum = sum.first;
    }
  }
  cout << best << "\n";
  fill(begin(bit), end(bit), 0);
  fill(begin(back), end(back), -1);
  auto &vec = sums[best_sum];
  for (int i = 0; i < vec.size(); i++) {
    auto [l, r] = vec[i];
    int k = query(l - 1) + 1;
    update(r, k, i);
    if (k == best) {
      l = n + 1;
      for (int j = r; j >= 0; j--) {
        if (best > 0 && bit[j] == best && vec[back[j]].second < l) {
          cout << vec[back[j]].first << " " << vec[back[j]].second << "\n";
          best--;
          l = vec[back[j]].first;
        }
      }
      break;
    }
  }
}
