source_code: import java.util.*;
  
  public class Main {
  	
  	public static class node implements Comparable<node>{
  		int l,r;
  		node(){}
  		node(int l,int r) {
  			this.l=l;
  			this.r=r;
  		}
  		@Override
  		public int compareTo(node rhs) {
  			return r-rhs.r;
  		}
  	}
  	
  	public static void main(String args[]){
  		Scanner in = new Scanner(System.in);
  		int a = in.nextInt();
  		int x[] = new int[a];
  		for(int n=0;n<a;n++){
  			x[n] = in.nextInt();
  		}
  		int max = 1;
  		int t = 0;
  		HashMap<Integer, ArrayList<node>> map = new HashMap<Integer, ArrayList<node>>();
  		for(int n=0;n<a;n++){
  			int num = 0;
  			for(int m=n;m<a;m++){
  				num += x[m];
  				node node = new node(n, m);
  				if(!map.containsKey(num)){
  					ArrayList<node> list = new ArrayList<node>();
  					list.add(node);
  					map.put(num, list);
  					if(max == 1)t = num;
  				}
  				else{
  					ArrayList<node> list = map.get(num);
  					int left = 0;
  					int right = list.size()-1;				
  					int res = list.size();
  					while(left <= right){
  						int mid = (left + right) >> 1;
  						//System.out.println(mid +" "+ left +" " +right);
  						if(list.get(mid).r >= n){
  							res = mid;
  							right = mid - 1;
  						}
  						else{
  							left = mid + 1;
  						}
  					}
  					if(res == list.size()){
  						list.add(node);
  						if(max < res+1){
  							max = res+1;
  							t = num;
  						}
  					}
  					else if(list.get(res).r>m){
  						list.set(res, node);
  						if(max < res){
  							max = list.size();
  							t = num;
  						}
  					}
  					
  				}
  			}
  		}
  		System.out.println(max);
  		for(int n=0;n<max;n++){
  			System.out.println((map.get(t).get(n).l+1)+" "+(map.get(t).get(n).r+1));
  		}
  		
  	}
  }