#include <bits/stdc++.h>
int a[1500], n;
int dp[1500][1500], ans_n;
std::pair<int, int> nxt[1500][1500], ans_ii;
std::map<int, std::pair<int, int> > mx;
int main() {
  scanf("%d", &n);
  for (int i = 0; i < n; ++i) scanf("%d", &a[i]);
  ans_n = 0;
  for (int i = 0; i < n; ++i) {
    int s = 0;
    for (int j = i; j < n; ++j) {
      s += a[j];
      dp[i][j] = 1;
      nxt[i][j] = std::pair<int, int>(-1, -1);
      {
        auto it = mx.find(s);
        if (it != mx.end()) {
          std::pair<int, int> x = (*it).second;
          int l = x.first;
          int r = x.second;
          if (dp[l][r] + 1 > dp[i][j]) {
            dp[i][j] = 1 + dp[l][r];
            nxt[i][j] = x;
          }
        }
      }
      if (ans_n < dp[i][j]) {
        ans_n = dp[i][j];
        ans_ii = std::pair<int, int>(i, j);
      }
    }
    for (int j = i, s = 0; j >= 0; --j) {
      int l = j;
      int r = i;
      s += a[j];
      {
        auto it = mx.find(s);
        if (it == mx.end()) {
          mx.insert(std::make_pair(s, std::pair<int, int>(l, r)));
        } else {
          std::pair<int, int> x = (*it).second;
          if (dp[x.first][x.second] < dp[l][r]) {
            (*it).second = std::pair<int, int>(l, r);
          }
        }
      }
    }
  }
  std::vector<std::pair<int, int> > ans_v;
  while (ans_ii.first >= 0 && ans_ii.second >= 0) {
    ans_v.push_back(ans_ii);
    int i = ans_ii.first, j = ans_ii.second;
    ans_ii = nxt[i][j];
  }
  std::reverse(ans_v.begin(), ans_v.end());
  printf("%d\n", ans_n);
  assert(ans_n == (int)ans_v.size());
  for (int i = 0; i < ans_n; ++i) {
    int l = ans_v[i].first + 1;
    int r = ans_v[i].second + 1;
    printf("%d %d\n", l, r);
  }
  return 0;
}
