#include <bits/stdc++.h>
using namespace std;
long long MAX = 0;
long long LIS[2250005], SAV[2250005], top, T, N, md[2250005], A[2250005], ans;
pair<long long, pair<long long, long long> > P[2250005];
pair<long long, long long> p[2250005];
pair<long long, long long> pans[2250005];
long long BS(long long x) {
  long long d = 0;
  long long c = top;
  while (d < c) {
    long long m = (d + c) / 2;
    if (SAV[m] <= x)
      d = m + 1;
    else
      c = m;
  }
  return d - 1;
}
void PTIT() {
  for (long long i = 1; i <= top; i++) SAV[i] = 777777777777777777;
  SAV[0] = -777777777777777777;
  for (long long i = 1; i <= top; i++) {
    LIS[i] = BS(p[i].second) + 1;
    SAV[LIS[i]] = min(SAV[LIS[i]], p[i].first);
  }
  for (long long i = 1; i <= top; i++) {
    MAX = max(MAX, LIS[i]);
  }
}
signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> N;
  md[0] = 0;
  for (long long i = 1; i <= N; i++) {
    cin >> A[i];
    md[i] = md[i - 1] + A[i];
  }
  long long TOP = 0;
  for (long long i = 0; i <= N; i++) {
    for (long long j = i + 1; j <= N; j++) {
      TOP++;
      P[TOP].first = md[j] - md[i];
      P[TOP].second.first = j;
      P[TOP].second.second = i;
    }
  }
  sort(P + 1, P + TOP + 1);
  P[TOP + 1].first = 777777777777777777;
  P[0].first = -777777777777777777;
  long long ans = 0;
  long long tmp = 0;
  long long Max = 0;
  for (long long i = 1; i <= TOP; i++) {
    tmp = P[i].first;
    if (P[i].first != P[i - 1].first) {
      top = 0;
    }
    top++;
    p[top].first = P[i].second.first;
    p[top].second = P[i].second.second;
    if (P[i].first != P[i + 1].first) {
      PTIT();
      if (MAX >= Max) {
        Max = MAX;
        ans = top;
        for (long long j = 1; j <= ans; j++) {
          pans[j].first = p[j].first;
          pans[j].second = p[j].second + 1;
        }
      }
      MAX = 0;
    }
  }
  cout << Max << endl;
  long long T = -1;
  for (long long i = 1; i <= ans; i++) {
    if (pans[i].second > T) {
      cout << pans[i].second << " " << pans[i].first << endl;
      T = pans[i].first;
    }
  }
  return 0;
}
