import java.util.Scanner;

public class Main {
	
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int j = 0;
		int[] a = new int[101];
		for (int i = 0; i < n ; i++) {
			int x = sc.nextInt();
			if(a[x]==0)
				++j;
			a[x]++;
		}
		System.out.println(j);
		for(int i = 1 ; i < 101 ; i++)
		{
			if(a[i]>0)
			System.out.println(i+" "+a[i]);
		}
	
	}
}
/**************************************************************
	Problem: 1725
	User: admin
	Language: Java
	Result: Accepted
	Time:4249 ms
	Memory:53956 kb
****************************************************************/