#include <bits/stdc++.h>
using namespace std;
const int N = 5000;
const int H = 1e9;
const int sx[4] = {1, -1, 0, 0};
const int sy[4] = {0, 0, 1, -1};
mt19937 gen(chrono::high_resolution_clock::now().time_since_epoch().count());
int main() {
  srand(time(0));
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  int a[n];
  for (auto &to : a) cin >> to;
  int pref[n + 1];
  for (int i = 0; i < n; ++i) {
    if (!i)
      pref[1] = a[i];
    else
      pref[i + 1] = pref[i] + a[i];
  }
  pref[0] = 0;
  map<int, vector<pair<int, int>>> lol;
  for (int i = 1; i <= n; ++i)
    for (int j = i; j <= n; ++j) lol[pref[j] - pref[i - 1]].push_back({j, i});
  vector<pair<int, int>> WANI4KA_LOXONYLCYA;
  for (auto to : lol) {
    vector<pair<int, int>> mem = to.second;
    vector<pair<int, int>> now;
    sort(mem.begin(), mem.end());
    int Wanickka_LOLLX = -1;
    for (auto ot : mem)
      if (Wanickka_LOLLX < ot.second)
        Wanickka_LOLLX = ot.first, now.push_back({ot.second, ot.first});
    if (WANI4KA_LOXONYLCYA.size() < now.size()) WANI4KA_LOXONYLCYA = now;
  }
  cout << WANI4KA_LOXONYLCYA.size() << '\n';
  for (auto to : WANI4KA_LOXONYLCYA)
    cout << to.first << " " << to.second << '\n';
  return 0;
}
