#include <bits/stdc++.h>
using namespace std;
long long mod = 1e9 + 7;
long long min(long long a, long long b) { return (a < b) ? a : b; }
long long max(long long a, long long b) { return (a > b) ? a : b; }
long long fp(long long a, long long b) {
  if (b == 0) return 1;
  long long x = fp(a, b / 2);
  x = (x * x) % mod;
  if (b & 1) x = (x * a) % mod;
  return x;
}
const long long N = 2000;
long long bit[4 * N];
void update(long long id, long long l, long long r, long long point,
            long long val) {
  if (point < l || point > r) return;
  if (l == r) {
    bit[id] += val;
    return;
  }
  long long mid = (l + r) / 2;
  update(2 * id, l, mid, point, val);
  update(2 * id + 1, mid + 1, r, point, val);
  bit[id] = bit[2 * id] + bit[2 * id + 1];
}
long long get(long long id, long long l, long long r, long long point) {
  if (point < l) {
    return 0;
  }
  if (r <= point) {
    return bit[id];
  }
  long long mid = (l + r) / 2;
  return get(2 * id, l, mid, point) + get(2 * id + 1, mid + 1, r, point);
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  long long n;
  cin >> n;
  long long a[n + 1];
  for (long long i = 1; i <= n; i++) {
    cin >> a[i];
  }
  map<long long, vector<array<long long, 2>>> mp;
  for (long long i = 1; i <= n; i++) {
    long long sm = 0;
    for (long long j = i; j <= n; j++) {
      sm += a[j];
      mp[sm].push_back({i, j});
    }
  }
  vector<array<long long, 2>> ans;
  for (auto i : mp) {
    vector<array<long long, 2>> tmp;
    sort(i.second.begin(), i.second.end());
    for (long long j = 0; j < i.second.size(); j++) {
      update(1, 1, n, i.second[j][1], 1);
    }
    long long st = 1;
    for (long long j = 0; j < i.second.size(); j++) {
      update(1, 1, n, i.second[j][1], -1);
      if (i.second[j][0] < st) continue;
      if (i.second[j][0] == i.second[j][1]) {
        tmp.push_back(i.second[j]);
        st = i.second[j][1] + 1;
      } else {
        long long x =
            get(1, 1, n, i.second[j][1] - 1) - get(1, 1, n, i.second[j][0]);
        if (x > 0) {
          continue;
        } else {
          tmp.push_back(i.second[j]);
          st = i.second[j][1] + 1;
        }
      }
    }
    if (tmp.size() > ans.size()) ans = tmp;
  }
  cout << ans.size() << "\n";
  for (auto i : ans) cout << i[0] << " " << i[1] << "\n";
}
