package q6;
import java.util.*;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		int m = sc.nextInt();
		int bef = -1;
		int start = -1;
		StringBuilder sb = new StringBuilder();
		int ans = 0;
		for(int i = 0;i < m;i++) {
			int a = sc.nextInt();
			if(bef != a - 1) {
				if(bef != -1) {
					sb.append(start + " " + (bef - start + 1) + "\n");
					ans++;
				}start = a;
			}bef = a;
		}sb.append(start + " " + (bef - start + 1) + "\n");
		ans++;
		
		System.out.print(ans + "\n" + sb);
	}

}