Andryusha is an orderly boy and likes to keep things in their place.

Today he faced a problem to put his socks in the wardrobe. He has n distinct pairs of socks which are initially in a bag. The pairs are numbered from 1 to n. Andryusha wants to put paired socks together and put them in the wardrobe. He takes the socks one by one from the bag, and for each sock he looks whether the pair of this sock has been already took out of the bag, or not. If not (that means the pair of this sock is still in the bag), he puts the current socks on the table in front of him. Otherwise, he puts both socks from the pair to the wardrobe.

Andryusha remembers the order in which he took the socks from the bag. Can you tell him what is the maximum number of socks that were on the table at the same time? 

Input

The first line contains the single integer n (1 ≤ n ≤ 105) — the number of sock pairs.

The second line contains 2n integers x1, x2, ..., x2n (1 ≤ xi ≤ n), which describe the order in which Andryusha took the socks from the bag. More precisely, xi means that the i-th sock Andryusha took out was from pair xi.

It is guaranteed that Andryusha took exactly two socks of each pair.

Output

Print single integer — the maximum number of socks that were on the table at the same time.

Examples

Input

1
1 1


Output

1


Input

3
2 1 1 3 2 3


Output

2

Note

In the first example Andryusha took a sock from the first pair and put it on the table. Then he took the next sock which is from the first pair as well, so he immediately puts both socks to the wardrobe. Thus, at most one sock was on the table at the same time.

In the second example Andryusha behaved as follows: 

  * Initially the table was empty, he took out a sock from pair 2 and put it on the table. 
  * Sock (2) was on the table. Andryusha took out a sock from pair 1 and put it on the table. 
  * Socks (1, 2) were on the table. Andryusha took out a sock from pair 1, and put this pair into the wardrobe. 
  * Sock (2) was on the table. Andryusha took out a sock from pair 3 and put it on the table. 
  * Socks (2, 3) were on the table. Andryusha took out a sock from pair 2, and put this pair into the wardrobe. 
  * Sock (3) was on the table. Andryusha took out a sock from pair 3 and put this pair into the wardrobe. 

Thus, at most two socks were on the table at the same time.
import java.util.*;
import java.math.*;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;

     //--------------->>>>IF YOU ARE HERE FOR QUICKSORT HACK THEN SORRY NO HACK FOR YOU<<<-------------------

public class a{ 
     static int[] count,count1,count2;
     static Node[] nodes;
     static long[] arr;
     static int[] dp,arrInt,darrInt;
     static char[] ch,ch1;
     static long[] darr,farr;
     static char[][] mat,mat1;
     static int[][] space;
     static boolean[][] vis;
     static long x,h;
     static long maxl;
     static double dec;
     static long mx = (long)1e10;
     static String s,s1,s2,s3,s4;
     static long minl;
     static int start_row;
     static int start_col;     
     static int end_row;     
     static int end_col;     
     static long mod = 998244353;
     // static int minl = -1;
     // static long n;
     static int n,n1,n2,q,r1,c1,r2,c2;
     static long a;
     static long b;
     static long c;
     static long d;
     static long y,z;
     static int m;
     static long k;
     static FastScanner sc;
     static String[] str,str1;
     static Set<Long> set,set1,set2;
     static SortedSet<Long> ss;
     static List<Character> list,list1,list2,list3;
     static PriorityQueue<Integer> pq,pq1;
     static LinkedList<Node> ll;
     static Map<Integer,List<Integer>> map1;
     static Map<String,Integer> map;
     static StringBuilder sb,sb1,sb2;
     static int index;
     static long[] sum;
     static int[] dx = {0,-1,0,1,-1,1,-1,1};
     static int[] dy = {-1,0,1,0,-1,-1,1,1};

     // public static void solve(){

     //    FastScanner sc = new FastScanner();
     //    // int t = sc.nextInt();
     //    int t = 1;
     //    for(int tt = 0 ; tt < t ; tt++){

     //        // s = sc.next();
     //        // s1 = sc.next();

     //        n = sc.nextInt();
     //        // m = sc.nextInt();
     //        // sb = new StringBuilder();
     //        // map = new HashMap<>();
     //        // q = sc.nextInt();
     //        // k = sc.nextLong();
     //        // ch = sc.next().toCharArray();
     //        // boolean ans = false;
     //        // int charge = n;
     //        // int prev = 0;

     //        // count = new int[7];
           
     //        // m = sc.nextInt();
     //        // double ans = mx*1.0;
     //        // long added = 0;
     //        set = new HashSet<>();

     //        for(int j = 0 ; j < n ; j++){

     //            // long l = sc.nextLong();
     //            // long r = sc.nextLong();

     //        }

     //        // System.out.println(ans);

     //    }
        
     // }

     //--------------->>>>IF YOU ARE HERE FOR QUICKSORT HACK THEN SORRY NO HACK FOR YOU<<<-------------------

     public static void solve(){

        set = new HashSet<>();
        long ans = 0;

        for(int i = 0 ; i < n ; i++){
            if(!set.contains(arr[i])){
                set.add(arr[i]);
            }
            else{
                set.remove(new Long(arr[i]));
            }
            ans = Math.max(ans,set.size());
        }

        System.out.println(ans);

     }
        
     public static void main(String[] args) {

            sc = new FastScanner();
            // Scanner sc = new Scanner(System.in);
            // int t = sc.nextInt();
            int t = 1;
            // int l = 1;
            while(t > 0){
                
                // n = sc.nextInt();
                // n = sc.nextLong();
                // k = sc.nextLong();
                // x = sc.nextLong();
                // y = sc.nextLong();
                // z = sc.nextLong();

                // a = sc.nextLong();
                // b = sc.nextLong();
                // c = sc.nextLong();
                // d = sc.nextLong();

                // x = sc.nextLong();
                // y = sc.nextLong();
                // z = sc.nextLong();
                // d = sc.nextLong();
                // n = sc.nextLong();

                n = 2*sc.nextInt();

                // n = 3;
                // n1 = sc.nextInt();

                // m = sc.nextInt();
                // q = sc.nextInt();

                // k = sc.nextLong();

                // x = sc.nextLong();
                // d = sc.nextLong();

                // s = sc.next();

                // ch = sc.next().toCharArray();
                // ch1 = sc.next().toCharArray();

                // n = 3;

                arr = new long[n];
                for(int i = 0 ; i < n ; i++){
                    arr[i] = sc.nextLong();
                }

                // arrInt = new int[n];
                // for(int i = 0 ; i < n ; i++){
                //     arrInt[i] = sc.nextInt();
                // }
                // x = sc.nextLong();
                // y = sc.nextLong();
                // ch = sc.next().toCharArray();
                // m = n;
                // darr = new long[m];
                // for(int i = 0 ; i < m ; i++){
                //     darr[i] = sc.nextLong();
                // }

                // m = n;
                // darrInt = new int[m];
                // for(int i = 0 ; i < m ; i++){
                //     darrInt[i] = sc.nextInt();
                // }

                // farr = new int[n];
                // for(int i = 0; i < n ; i++){
                //     farr[i] = sc.nextInt();
                // }

                // mat = new long[n][m];
                // for(int i = 0 ; i < n ; i++){
                //     for(int j = 0 ; j < m ; j++){
                //         mat[i][j] = sc.nextLong();
                //     }
                // }

                // m = n;
                // mat = new char[n][m];
                // for(int i = 0 ; i < n ; i++){
                //     String s = sc.next();
                //     for(int j = 0 ; j < m ; j++){
                //         mat[i][j] = s.charAt(j);
                //     }
                // }

                // m = n;
                // mat1 = new char[n][m];
                // for(int i = 0 ; i < n ; i++){
                //     String s = sc.next();
                //     for(int j = 0 ; j < m ; j++){
                //         mat1[i][j] = s.charAt(j);
                //     }
                // }

                // n= 5 ;
                // str = new String[n];
                // for(int i = 0 ; i < n ; i++)
                //     str[i] = sc.next();

                // nodes = new Node[n];
                // for(int i = 0 ; i < n ;i++)
                //     nodes[i] = new Node(sc.nextInt(),(i+1));

                // m = sc.nextInt();

                // System.out.println(solve()?"YES":"NO");
                 solve();       
                 // System.out.println(solve());
                 t -= 1;
            }

     }

     // public static dfs(int i){

     //    if(count[i] == 1)
     //        return;
     //    list = map.get(i);
     //    for(Integer j : list){
     //        if(j == i)
     //            continue;
     //        dfs(j);
     //    }
     // }

    public static int log(long n,long base){

         if(n == 0 || n == 1)
             return 0;

         if(n == base)
             return 1;

         double num = Math.log(n);
         double den = Math.log(base);

         if(den == 0)
             return 0;

         return (int)(num/den);
     }

    public static boolean isPrime(long n) { 
    // Corner cases 
        if (n <= 1)  
            return false; 

        if (n <= 3)  
            return true; 
      
        // This is checked so that we can skip  
        // middle five numbers in below loop 
        if (n%2 == 0 || n%3 == 0) 
            return false; 
      
        for (int i=5; i*i<=n; i=i+6) 
            if (n%i == 0 || n%(i+2) == 0) 
               return false; 
      
        return true; 
    } 

    public static long gcd(long a, long b)
    {
      if (b == 0)
        return a;
      return gcd(b, a % b); 
    }

     public static long mod_inverse(long a,long mod){
        long x1=1,x2=0;
        long p=mod,q,t;
        while(a%p!=0){
          q = a/p;
          t = x1-q*x2;
          x1=x2; x2=t;
          t=a%p;
          a=p; p=t;
        }
        return x2<0 ? x2+mod : x2;
    }

     public static void swap(int i,int j){
         long temp = arr[j];
         arr[j] = arr[i];
         arr[i] = temp;
     } 

    static final Random random=new Random();

    static void ruffleSortLong(long[] a) {
        int n=a.length;//shuffle, then sort 
        for (int i=0; i<n; i++) {
            int oi=random.nextInt(n);
            long temp=a[oi];
            a[oi]=a[i]; a[i]=temp;
        }
        Arrays.sort(a);
    }

    static void ruffleSortInt(int[] a) {
        int n=a.length;//shuffle, then sort 
        for (int i=0; i<n; i++) {
            int oi=random.nextInt(n);
            int temp=a[oi];
            a[oi]=a[i]; a[i]=temp;
        }
        Arrays.sort(a);
    }
    
    static void ruffleSortChar(char[] a) {
        int n=a.length;//shuffle, then sort 
        for (int i=0; i<n; i++) {
            int oi=random.nextInt(n);
            char temp=a[oi];
            a[oi]=a[i]; a[i]=temp;
        }
        Arrays.sort(a);
    }

    static class Node{
        Integer first;
        Integer second;
        Node(Integer f,Integer s){
            this.first = f;
            this.second = s;
        }
    }

     static class FastScanner {

                BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
                StringTokenizer st=new StringTokenizer("");
                String next() {
                        while (!st.hasMoreTokens())
                                try {
                                        st=new StringTokenizer(br.readLine());
                                } catch (IOException e) {
                                        e.printStackTrace();
                                }
                        return st.nextToken();
                }
                
                int nextInt() {
                        return Integer.parseInt(next());
                }
                int[] readArray(int n) {
                        int[] a=new int[n];
                        for (int i=0; i<n; i++) a[i]=nextInt();
                        return a;
                }
                long nextLong() {
                        return Long.parseLong(next());
                }
        }

}