source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.io.PrintWriter;
  import java.io.BufferedWriter;
  import java.util.HashMap;
  import java.util.InputMismatchException;
  import java.io.IOException;
  import java.util.List;
  import java.util.Map;
  import java.io.Writer;
  import java.io.OutputStreamWriter;
  import java.util.LinkedList;
  import java.util.Comparator;
  import java.util.Collections;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   */
  public class Main {
      public static void main(String[] args) {
          InputStream inputStream = System.in;
          OutputStream outputStream = System.out;
          InputReader in = new InputReader(inputStream);
          OutputWriter out = new OutputWriter(outputStream);
          Task547F solver = new Task547F();
          solver.solve(1, in, out);
          out.close();
      }
  
      static class Task547F {
          public void solve(int testNumber, InputReader in, OutputWriter out) {
              int n = in.nextInt();
              long arr[] = in.nextLongArray(n);
              long cur = 0;
              int i, j;
              Map<Long, List<Pair>> hm = new HashMap<>();
  
              for (i = 0; i < n; i++) {
                  cur = 0;
                  for (j = i; j < n; j++) {
                      cur += arr[j];
                      if (!hm.containsKey(cur)) {
                          List<Pair> al = new LinkedList<>();
                          al.add(new Pair(i + 1, j + 1));
                          hm.put(cur, al);
                      } else {
                          List<Pair> al = hm.get(cur);
                          al.add(new Pair(i + 1, j + 1));
                          hm.put(cur, al);
                      }
                  }
              }
              //out.println(hm);
              long max = arr[0];
              int msize = 0;
              for (long key : hm.keySet()) {
                  List<Pair> al = hm.get(key);
                  if (al.size() < hm.get(max).size())
                      continue;
                  Collections.sort(al, new Comparator<Pair>() {
  
                      public int compare(Pair o1, Pair o2) {
                          if (o1.b != o2.b)
                              return o1.b - o2.b;
                          return o1.a - o2.a;
                      }
                  });
                  //out.println(al);
                  List<Pair> all = new LinkedList<>();
                  int prev = -1;
                  for (Pair p : al) {
                      if (p.a > prev) {
                          all.add(p);
                          prev = p.b;
                      }
                  }
                  //out.println(all);
  
                  hm.put(key, all);
                  //out.println(all.size());
                  if (all.size() > msize) {
                      //out.println("ca" + msize + " " + all.size());
                      msize = all.size();
                      max = key;
                  }
  
              }
              //out.println(hm);
  
              List<Pair> al = hm.get(max);
              out.println(al.size());
              for (Pair p : al) {
                  out.println(p.a + " " + p.b);
              }
  
          }
  
          class Pair {
              int a;
              int b;
  
              public Pair(int a, int b) {
                  this.a = a;
                  this.b = b;
              }
  
              public String toString() {
                  return "(" + a + ", " + b + ")";
              }
  
          }
  
      }
  
      static class InputReader {
          private InputStream stream;
          private byte[] buf = new byte[1024];
          private int curChar;
          private int numChars;
          private InputReader.SpaceCharFilter filter;
  
          public InputReader(InputStream stream) {
              this.stream = stream;
          }
  
          public 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 (isSpaceChar(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 (!isSpaceChar(c));
              return res * sgn;
          }
  
          public long nextLong() {
              int c = read();
              while (isSpaceChar(c)) {
                  c = read();
              }
              int sgn = 1;
              if (c == '-') {
                  sgn = -1;
                  c = read();
              }
              long res = 0;
              do {
                  if (c < '0' || c > '9') {
                      throw new InputMismatchException();
                  }
                  res *= 10;
                  res += c - '0';
                  c = read();
              } while (!isSpaceChar(c));
              return res * sgn;
          }
  
          public boolean isSpaceChar(int c) {
              if (filter != null) {
                  return filter.isSpaceChar(c);
              }
              return isWhitespace(c);
          }
  
          public static boolean isWhitespace(int c) {
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
          public long[] nextLongArray(int n) {
              long[] array = new long[n];
              for (int i = 0; i < n; ++i) array[i] = nextLong();
              return array;
          }
  
          public interface SpaceCharFilter {
              public boolean isSpaceChar(int ch);
  
          }
  
      }
  
      static class OutputWriter {
          private final PrintWriter writer;
  
          public OutputWriter(OutputStream outputStream) {
              writer = new PrintWriter(new BufferedWriter(new OutputStreamWriter(outputStream)));
          }
  
          public OutputWriter(Writer writer) {
              this.writer = new PrintWriter(writer);
          }
  
          public void print(Object... objects) {
              for (int i = 0; i < objects.length; i++) {
                  if (i != 0) {
                      writer.print(' ');
                  }
                  writer.print(objects[i]);
              }
          }
  
          public void println(Object... objects) {
              print(objects);
              writer.println();
          }
  
          public void close() {
              writer.close();
          }
  
          public void println(int i) {
              writer.println(i);
          }
  
      }
  }
  
  