source_code: import java.io.BufferedReader;
  import java.io.IOException;
  import java.io.InputStreamReader;
  import java.io.PrintWriter;
  import java.util.Comparator;
  import java.util.HashMap;
  import java.util.TreeMap;
  
  public class Main extends PrintWriter {
  
      static BufferedReader s = new BufferedReader(new InputStreamReader(System.in));
      // static Scanner s=new Scanner(System.in);
      Main () { super(System.out); }
      public static void main(String[] args) throws IOException{
          Main  d1=new Main   ();d1.main();d1.flush();
      }
      void main() throws IOException {
          BufferedReader s = new BufferedReader(new InputStreamReader(System.in));
          StringBuffer sb = new StringBuffer();
          StringBuffer sb1 = new StringBuffer();
          PrintWriter out = new PrintWriter(System.out);
          int t=1;
  //        t=i(s()[0]);
          while(t-->0) {
              //dp[i]=a[i]+max(dp[j]) S.T. j<i and h[j]<h[i];
              String[] s1 = s();
              int n = i(s1[0]);
               long[] a=new long[n];
               arr(a,n);
               HashMap<Long,Integer>[] dp=new HashMap[n];
  
               long[] presum=new long[n];
               for(int i=0;i<n;i++){
                   if(i==0){
                       presum[i]=a[i];
                   }else{
                       presum[i]=a[i]+presum[i-1];
                   }
               }HashMap<Long,TreeMap<Integer,Long> > tm=new HashMap<>();int ans=0;long maxsum=0;
               for(int i=0;i<n;i++){
                    dp[i]=new HashMap<>();
                   for(int j=-1;j<i;j++){
                       long sum=0;
                       if(j==-1) sum=presum[i];else sum=presum[i]-presum[j];
  //                     if(sum==5&&i==5) System.out.println(tm.get(sum).floorKey(4));
                       if(tm.containsKey(sum)&&tm.get(sum).floorKey(j)!=null){
                           dp[i].put(sum,Math.max(dp[i].getOrDefault(sum,0),dp[tm.get(sum).floorKey(j)].getOrDefault(sum,0)+1));
                          if(dp[i].get(sum)>ans){
                              maxsum=sum;
                          }
                           ans=Math.max(ans,dp[i].get(sum));
                       }else if(dp[i].containsKey(sum)==false){
                           if(dp[i].getOrDefault(sum,0)<1) dp[i].put(sum,1);
                           if(dp[i].get(sum)>ans){
                               maxsum=sum;
                           }
                           ans=Math.max(ans,1);
                       }
                       long val=dp[i].getOrDefault(sum,0);
  //                     if(tm.containsKey(sum)&&tm.get(sum).floorKey(i-1)!=null){
                           if(!tm.containsKey(sum)||tm.get(sum).floorKey(i-1)==null||dp[tm.get(sum).floorKey(i-1)].getOrDefault(sum,0)<val) {
  //                             val = Math.max(val, dp[tm.get(sum).floorKey(i - 1)].getOrDefault(sum, 0));
                               TreeMap<Integer, Long> tt = new TreeMap<>();
                               tt.put(i, val);
                               tm.put(sum, tt);
                           }
  //                     }
                       }
               }int cnt=0;int last=-1;
               for(int i=0;i<n;i++){
                   for(int j=i-1;j>=-1;j--){
                       long sum=0;
                       if(j==-1) sum=presum[i];
                       else sum=presum[i]-presum[j];
                       if(dp[i].getOrDefault(maxsum,0)>cnt&&maxsum==sum){
                           sb.append(j+2+" "+(i+1)+"\n");cnt++;
                           break;
                       }
                   }
               } System.out.println(ans);
  //            System.out.println(dp[5].get(5L)+" "+dp[4].get(5L));
              System.out.println(sb);
          }
  
      }
      //        System.out.println(sb);
      long[] st;
      void buildtree(int i,int s,int e,long[] a){
          if(s==e){
              st[i]=a[s];
              return;
          }
          int mid=(s+e)/2;
          buildtree(2*i,s,mid,a);
          buildtree(2*i+1,mid+1,e,a);
          st[i]=Math.min(st[2*i],st[2*(i)+1]);
      }
      long query(int i,int s,int e,int qs,int qe){
          if(qs>e||qe<s) return Integer.MIN_VALUE;
          if(s>=qs&&e<=qe) return st[i];
          int mid=(s+e)/2;
          long l=query(2*i,s,mid,qs,qe);
          long r=query(2*i+1,mid+1,e,qs,qe);
          return Math.max(l,r);
      }
      void pointupdate(int i,int s,int e,int qi,long [] a){
          if(s==e){
              st[i]=a[s];return;
          }
          int mid=(s+e)/2;
          if(qi<=mid) pointupdate(2*i,s,mid,qi,a);
          else pointupdate(2*(i)+1,mid+1,e,qi,a);
          st[i]=Math.max(st[2*i],st[2*i+1]);
      }
      public void arr(long[] a,int n) throws IOException{
          //        BufferedReader s = new BufferedReader(new InputStreamReader(System.in));
          String[] s2=s();
          for(int i=0;i<n;i++){
              a[i]=i(s2[i]);
          }
      }
      public void sort(int[] a,int l,int h){
          if(l==h) return;
          int mid=(l+h)/2;
  
          sort(a,l,mid);
          sort(a,mid+1,h);
          merge(a,l,(l+h)/2,h);
      }
      void merge(int arr[], int l, int m, int r)
      {
          int n1 = m - l + 1;
          int n2 = r - m;
          int L[] = new int[n1];
          int R[] = new int[n2];
          for (int i = 0; i < n1; ++i)
              L[i] = arr[l + i];
          for (int j = 0; j < n2; ++j)
              R[j] = arr[m + 1 + j];
          int i = 0, j = 0;
          int k = l;
          while (i < n1 && j < n2) {
              if (L[i] <= R[j]) {
                  arr[k] = L[i];
                  i++;
              }
              else {
                  arr[k] = R[j];
                  j++;
              }
              k++;
          }
  
          while (i < n1) {
              arr[k] = L[i];
              i++;
              k++;
          }
          while (j < n2) {
              arr[k] = R[j];
              j++;
              k++;
          }
      }
  
  
      static long gcd(long a, long b) {
          if (b == 0)
              return a;
          return gcd(b, a % b);
      }
      static String[] s() throws IOException {
          return s.readLine().trim().split("\\s+");
      }
  
      static int i(String ss) {
          return Integer.parseInt(ss);
      }
      static long l(String ss) {
          return Long.parseLong(ss);
      }
  }
  class Student {
      long  a;int b;int c;
      public Student(int a,int b) {
          this.a=a;this.c=c;this.b=b;
      }
  }
  class Pair {
      int  a,b,c;
      public Pair(int  a,int b){
          this.a=a;this.b=b;this.c=c;}
  }
  class Sortbyroll implements Comparator<Student> {
  
      public int compare(Student a, Student b){
          if(a.b==b.b) return (int)b.a-(int)a.a;
          return   a.b-b.b;}
  }