One day Jeff got hold of an integer sequence a1, a2, ..., an of length n. The boy immediately decided to analyze the sequence. For that, he needs to find all values of x, for which these conditions hold:

  * x occurs in sequence a. 
  * Consider all positions of numbers x in the sequence a (such i, that ai = x). These numbers, sorted in the increasing order, must form an arithmetic progression. 



Help Jeff, find all x that meet the problem conditions.

Input

The first line contains integer n (1 ≤ n ≤ 105). The next line contains integers a1, a2, ..., an (1 ≤ ai ≤ 105). The numbers are separated by spaces.

Output

In the first line print integer t — the number of valid x. On each of the next t lines print two integers x and px, where x is current suitable value, px is the common difference between numbers in the progression (if x occurs exactly once in the sequence, px must equal 0). Print the pairs in the order of increasing x.

Examples

Input

1
2


Output

1
2 0


Input

8
1 2 1 3 1 2 1 5


Output

4
1 2
2 4
3 0
5 0

Note

In the first test 2 occurs exactly once in the sequence, ergo p2 = 0.
import com.sun.corba.se.spi.orb.ParserImplBase;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.*;

/**
 * Created with IntelliJ IDEA.
 * User: AUtemuratov
 * Date: 07.04.14
 * Time: 15:43
 * To change this template use File | Settings | File Templates.
 */
public class Main {
    static FastReader fr = new FastReader(new BufferedReader(new InputStreamReader(System.in)));
    static PrintWriter pw = new PrintWriter(System.out);
    static int n,m,cnt;
    static Pair a[] = new Pair[1111111];
    static boolean u[] = new boolean[11111111];
    static StringBuilder s = new StringBuilder();

    public static void main(String[] args) throws Exception {

        n = fr.nextInt();

        for (int i=1; i<=100000; i++) {
            a[i] = new Pair(0,0);
        }

        for (int i=1; i<=n; i++) {
            int t = fr.nextInt();
            u[t] = true;
            if (a[t].pos==-1) continue;

            if (a[t].pos!=0) {

                int at = (i - a[t].pos);
                if ((at == a[t].dif) || a[t].dif==0) {
                    a[t].pos = i;
                    a[t].dif = at;
                } else {
                    a[t].pos = -1;
                }
            } else {
                a[t] = new Pair(i,0);
            }
        }

        for (int i=1; i<=100000; i++) {
            if (a[i].pos!=-1 && u[i]) {
                cnt++;
                s.append(i + " " + a[i].dif + "\n");
            }
        }

        pw.println(cnt);
        pw.println(s);

        pw.close();
    }

}

class Pair {
    int pos,dif;
    public Pair(int pos, int dif) {
        this.pos = pos;
        this.dif = dif;
    }
    public Pair(int pos) {
        this.pos = pos;
        this.dif = 0;
    }
}

class FastReader {

    BufferedReader bf;
    StringTokenizer tk = null;
    String DELIM = " ";

    public FastReader(BufferedReader bf) {
        this.bf = bf;
    }

    public String nextToken() throws Exception {

        if(tk==null || !tk.hasMoreTokens()) {
            tk = new StringTokenizer(bf.readLine(),DELIM);
        }
        return tk.nextToken();
    }

    public int nextInt() throws Exception {
        return Integer.parseInt(nextToken());
    }

    public int nextLong() throws Exception {
        return Integer.parseInt(nextToken());
    }

    public int nextDouble() throws Exception {
        return Integer.parseInt(nextToken());
    }
}