source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.util.HashMap;
  import java.util.InputMismatchException;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author beginner1010
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          PrintWriter out = new PrintWriter(outputStream);
          TaskF2 solver = new TaskF2();
          solver.solve(1, in, out);
          out.close();
      }
  
      static class TaskF2 {
          public void solve(int testNumber, InputReader in, PrintWriter out) {
              int n = in.nextInt();
              int[] a = new int[n];
              for (int i = 0; i < n; i++) {
                  a[i] = in.nextInt();
              }
              HashMap<Integer, Integer> lastIndex = new HashMap<>();
              HashMap<Integer, Integer> maxSize = new HashMap<>();
              for (int i = 0; i < n; i++) {
                  int sum = 0;
                  for (int j = i; j < n; j++) {
                      sum += a[j];
                      if (maxSize.containsKey(sum) == false) {
                          maxSize.put(sum, 0);
                      }
                      int curMaxSize = maxSize.get(sum);
                      int curLastIndex = curMaxSize == 0 ? -1 : lastIndex.get(sum);
                      if (curMaxSize == 0 || curLastIndex < i) {
                          curMaxSize++;
                          curLastIndex = j;
                      } else if (curLastIndex >= j) {
                          curLastIndex = j;
                      }
                      maxSize.put(sum, curMaxSize);
                      lastIndex.put(sum, curLastIndex);
                  }
              }
  
              int bestSum = -1;
              int bestSize = -1;
              for (int sum : maxSize.keySet()) {
                  if (maxSize.get(sum) > bestSize) {
                      bestSize = maxSize.get(sum);
                      bestSum = sum;
                  }
              }
  
              ArrayList<Interval> best = new ArrayList<>();
              lastIndex = new HashMap<>();
              maxSize = new HashMap<>();
              for (int i = 0; i < n; i++) {
                  int sum = 0;
                  for (int j = i; j < n; j++) {
                      sum += a[j];
                      if (sum != bestSum)
                          continue; // consider only bestSums
                      if (maxSize.containsKey(sum) == false) {
                          maxSize.put(sum, 0);
                      }
                      int curMaxSize = maxSize.get(sum);
                      int curLastIndex = curMaxSize == 0 ? -1 : lastIndex.get(sum);
                      if (curMaxSize == 0 || curLastIndex < i) {
                          curMaxSize++;
                          curLastIndex = j;
                          best.add(new Interval(i, j));
                      } else if (curLastIndex >= j) {
                          curLastIndex = j;
                          best.set(best.size() - 1, new Interval(i, j));
                      }
                      maxSize.put(sum, curMaxSize);
                      lastIndex.put(sum, curLastIndex);
                  }
              }
  
              out.println(bestSize);
              for (Interval i : best) {
                  out.println((i.l + 1) + " " + (i.r + 1));
              }
          }
  
          class Interval {
              int l;
              int r;
  
              Interval(int l, int r) {
                  this.l = l;
                  this.r = r;
              }
  
          }
  
      }
  
      static class InputReader {
          private byte[] buf = new byte[1024];
          private int curChar;
          private int numChars;
          private InputStream stream;
  
          public InputReader(InputStream stream) {
              this.stream = stream;
          }
  
          private boolean isWhitespace(int c) {
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
          private int read() {
              if (numChars == -1)
                  throw new InputMismatchException();
              if (curChar >= numChars) {
                  curChar = 0;
                  try {
                      numChars = stream.read(buf);
                  } catch (IOException e) {
                      throw new InputMismatchException();
                  }
                  if (numChars <= 0)
                      return -1;
              }
              return buf[curChar++];
          }
  
          public int nextInt() {
              int c = read();
              while (isWhitespace(c))
                  c = read();
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              int res = 0;
              do {
                  if (c < '0' || c > '9')
                      throw new InputMismatchException();
                  res *= 10;
                  res += c - '0';
                  c = read();
              } while (!isWhitespace(c));
              return res * sgn;
          }
  
      }
  }
  
  