source_code: import java.io.OutputStream;
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.PrintWriter;
  import java.util.InputMismatchException;
  import java.util.HashMap;
  import java.io.IOException;
  import java.util.ArrayList;
  import java.util.List;
  import java.util.Map;
  import java.io.InputStream;
  
  /**
   * Built using CHelper plug-in Actual solution is at the top
   *
   * @author MaxHeap
   */
  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);
      F1SameSumBlocksEasy solver = new F1SameSumBlocksEasy();
      solver.solve(1, in, out);
      out.close();
    }
  
    static class F1SameSumBlocksEasy {
  
      Map<Long, List<IntPair>> sums = new HashMap<>();
  
      public void solve(int testNumber, InputReader in, PrintWriter out) {
        int n = in.nextInt();
        long[] arr = in.nextLongArray(n);
        long[] pref = ArrayUtils.prefixSum(arr);
        for (int i = 0; i < n; ++i) {
          for (int j = i; j >= 0; --j) {
            long sum = pref[i + 1] - pref[j];
            if (sums.containsKey(sum)) {
              sums.get(sum).add(Factories.makeIntPair(j, i));
            } else {
              List<IntPair> pairs = new ArrayList<>();
              pairs.add(Factories.makeIntPair(j, i));
              sums.put(sum, pairs);
            }
          }
        }
  
        int best = 0;
        List<IntPair> res = new ArrayList<>();
        for (long sum : sums.keySet()) {
          List<IntPair> pairs = sums.get(sum);
          List<IntPair> temp = new ArrayList<>();
          int last = -1;
          for (IntPair cur : pairs) {
            if (cur.first > last) {
              last = cur.second;
              temp.add(cur);
            }
          }
          if (temp.size() > best) {
            best = temp.size();
            res = temp;
          }
        }
        out.println(best);
        for (IntPair pair : res) {
          out.println((pair.first + 1) + " " + (pair.second + 1));
        }
      }
  
    }
  
    static class ArrayUtils {
  
      public static long[] prefixSum(long[] arr) {
        long[] acc = new long[arr.length + 1];
        for (int i = 1; i <= arr.length; ++i) {
          acc[i] = acc[i - 1] + arr[i - 1];
        }
        return acc;
      }
  
    }
  
    static interface FastIO {
  
    }
  
    static final class Factories {
  
      private Factories() {
      }
  
      public static IntPair makeIntPair(int first, int second) {
        return new IntPair(first, second);
      }
  
    }
  
    static class IntPair implements Comparable<IntPair> {
  
      public int first;
      public int second;
  
      public IntPair() {
        first = second = 0;
      }
  
      public IntPair(int first, int second) {
        this.first = first;
        this.second = second;
      }
  
      public int compareTo(IntPair a) {
        if (first == a.first) {
          return Integer.compare(second, a.second);
        }
        return Integer.compare(first, a.first);
      }
  
      public String toString() {
        return "<" + first + ", " + second + ">";
      }
  
      public boolean equals(Object o) {
        if (this == o) {
          return true;
        }
        if (o == null || getClass() != o.getClass()) {
          return false;
        }
  
        IntPair a = (IntPair) o;
  
        if (first != a.first) {
          return false;
        }
        return second == a.second;
      }
  
      public int hashCode() {
        int result = first;
        result = 31 * result + second;
        return result;
      }
  
    }
  
    static class InputReader implements FastIO {
  
      private InputStream stream;
      private static final int DEFAULT_BUFFER_SIZE = 1 << 16;
      private static final int EOF = -1;
      private byte[] buf = new byte[DEFAULT_BUFFER_SIZE];
      private int curChar;
      private int numChars;
  
      public InputReader(InputStream stream) {
        this.stream = stream;
      }
  
      public int read() {
        if (this.numChars == EOF) {
          throw new UnknownError();
        } else {
          if (this.curChar >= this.numChars) {
            this.curChar = 0;
  
            try {
              this.numChars = this.stream.read(this.buf);
            } catch (IOException ex) {
              throw new InputMismatchException();
            }
  
            if (this.numChars <= 0) {
              return EOF;
            }
          }
  
          return this.buf[this.curChar++];
        }
      }
  
      public int nextInt() {
        int c;
        for (c = this.read(); isSpaceChar(c); c = this.read()) {
        }
  
        byte sgn = 1;
        if (c == 45) {
          sgn = -1;
          c = this.read();
        }
  
        int res = 0;
  
        while (c >= 48 && c <= 57) {
          res *= 10;
          res += c - 48;
          c = this.read();
          if (isSpaceChar(c)) {
            return res * sgn;
          }
        }
  
        throw new InputMismatchException();
      }
  
      public long nextLong() {
        int c;
        for (c = this.read(); isSpaceChar(c); c = this.read()) {
        }
  
        byte sgn = 1;
        if (c == 45) {
          sgn = -1;
          c = this.read();
        }
  
        long res = 0;
  
        while (c >= 48 && c <= 57) {
          res *= 10L;
          res += c - 48;
          c = this.read();
          if (isSpaceChar(c)) {
            return res * sgn;
          }
        }
        throw new InputMismatchException();
      }
  
      public static boolean isSpaceChar(int c) {
        return c == 32 || c == 10 || c == 13 || c == 9 || c == EOF;
      }
  
      public long[] nextLongArray(int n) {
        long[] arr = new long[n];
        for (int i = 0; i < n; i++) {
          arr[i] = nextLong();
        }
        return arr;
      }
  
    }
  }
  
  