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.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.io.Writer;
  import java.io.OutputStreamWriter;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in
   * Actual solution is at the top
   *
   * @author prakharjain
   */
  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);
          F2SameSumBlocksHard solver = new F2SameSumBlocksHard();
          solver.solve(1, in, out);
          out.close();
      }
  
      static class F2SameSumBlocksHard {
          public void solve(int testNumber, InputReader in, OutputWriter out) {
              int n = in.nextInt();
  
              long[] a = in.nextLongArray(n);
  
              long[] p = in.calculatePrefixSum(a);
  
              Map<Long, Integer> map = new HashMap<>();
  
              for (int i = 0; i < n; i++) {
                  long sum = 0;
                  for (int j = i; j < n; j++) {
                      sum += a[j];
                      map.merge(sum, 1, (x, y) -> x + y);
                  }
              }
  
              List<sum> sums = new ArrayList<>();
              for (long sum : map.keySet()) {
                  sums.add(new sum(sum, map.get(sum)));
              }
  
              sums.sort((x, y) -> y.c - x.c);
  
              int ans = -1;
  
              int[] fca = null;
              long mxsum = -1;
              for (int i = 0; i < sums.size(); i++) {
                  sum cs = sums.get(i);
                  long sum = cs.sum;
                  long c = cs.c;
  
                  if (c < ans) {
                      continue;
                  }
  
                  Map<Long, Integer> lm = new HashMap<>();
  
                  int[] ca = new int[n];
                  lm.put(0l, -1);
                  for (int j = 0; j < n; j++) {
                      long val = p[j];
  
                      if (j > 0) {
                          ca[j] = ca[j - 1];
                      }
                      long req = val - sum;
  
                      if (lm.containsKey(req)) {
                          int li = lm.get(req);
                          if (li == -1)
                              ca[j] = Math.max(1, ca[j]);
                          else
                              ca[j] = Math.max(1 + ca[li], ca[j]);
                      }
  
                      lm.put(val, j);
                  }
  
                  if (ca[n - 1] > ans) {
                      ans = ca[n - 1];
                      mxsum = sum;
                      fca = ca;
                  }
              }
  
              List<Integer> al = new ArrayList<>();
  
              long sum = 0;
              for (int i = n - 1; i >= 0; i--) {
                  if (i > 0 && fca[i] != fca[i - 1]) {
                      sum = 0;
                      al.add(i + 1);
                      do {
                          sum += a[i];
                          i--;
                      } while (i >= 0 && sum != mxsum);
                      i++;
                      al.add(i + 1);
                  } else if (i == 0) {
                      if (a[i] == mxsum) {
                          al.add(i + 1);
                          al.add(i + 1);
                      }
                  }
              }
  
              out.println(al.size() / 2);
  
              for (int i = al.size() - 1; i >= 0; i -= 2) {
                  out.println(al.get(i) + " " + al.get(i - 1));
              }
          }
  
          class sum {
              long sum;
              int c;
  
              public sum(long sum, int c) {
                  this.sum = sum;
                  this.c = c;
              }
  
          }
  
      }
  
      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 static boolean isWhitespace(int c) {
              return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
          }
  
          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 long[] nextLongArray(int n) {
              long[] array = new long[n];
              for (int i = 0; i < n; ++i) array[i] = nextLong();
              return array;
          }
  
          public long[] calculatePrefixSum(long[] a) {
              int n = a.length;
  
              long[] prefixSum = new long[n];
  
              prefixSum[0] = a[0];
  
              for (int i = 1; i < n; i++) {
                  prefixSum[i] = prefixSum[i - 1] + a[i];
              }
  
              return prefixSum;
          }
  
          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);
          }
  
      }
  }
  
  