source_code: /*
  If you want to aim high, aim high
  Don't let that studying and grades consume you
  Just live life young
  ******************************
  If I'm the sun, you're the moon
  Because when I go up, you go down
  *******************************
  I'm working for the day I will surpass you
  https://www.a2oj.com/Ladder16.html
  */
  import java.util.*;
  import java.io.*;
  import java.math.*;
  
     public class x1141F
     {
        public static void main(String omkar[]) throws Exception
        {
           BufferedReader infile = new BufferedReader(new InputStreamReader(System.in));  
           StringTokenizer st = new StringTokenizer(infile.readLine());
           int N = Integer.parseInt(st.nextToken());
           int[] arr = new int[N];
           st = new StringTokenizer(infile.readLine());
           for(int i=0; i < N; i++)
              arr[i] = Integer.parseInt(st.nextToken());
           HashMap<Long, ArrayList<Integer>> map = new HashMap<Long, ArrayList<Integer>>();
           for(int r=0; r < N; r++)
           {
              long sum = 0L;
              for(int i=r; i >= 0; i--)
              {
                 sum += arr[i];
                 if(!map.containsKey(sum))
                    map.put(sum, new ArrayList<Integer>());
                 map.get(sum).add(i);
                 map.get(sum).add(r);
              }
           }
           ArrayList<Integer> res = new ArrayList<Integer>();
           for(long key: map.keySet())
           {
              ArrayList<Integer> ls = map.get(key);
              ArrayList<Integer> temp = new ArrayList<Integer>();
              temp.add(ls.get(0));
              temp.add(ls.get(1));
              int r = ls.get(1);
              for(int i=2; i < ls.size(); i+=2)
                 if(r < ls.get(i))
                 {
                    r = ls.get(i+1);
                    temp.add(ls.get(i));
                    temp.add(ls.get(i+1));
                 }
              if(res.size() < temp.size())
                 res = temp;
           }
           System.out.println(res.size()/2);
           StringBuilder sb = new StringBuilder();
           for(int i=0; i < res.size(); i+=2)
           {
              sb.append((1+res.get(i))+" "+(1+res.get(i+1)));
              sb.append("\n");
           }
           System.out.print(sb);
        }
     }