import java.util.*;

public class Main {
    static final int MOD = 1000000007;
	public static void main (String[] args) {
		Scanner sc = new Scanner(System.in);
		long d = sc.nextLong();
		int q = sc.nextInt();
		PriorityQueue<Work> queue = new PriorityQueue<>();
		PriorityQueue<Work> next = new PriorityQueue<>();
		StringBuilder sb = new StringBuilder();
		for (int i = 0; i < q; i++) {
		    queue.add(new Work(sc.nextLong(), sc.nextLong()));
		    Work prev = queue.poll();
		    long max = prev.getCount();
		    while (queue.size() > 0) {
		        Work x = queue.poll();
		        if (prev.end >= x.start - 1) {
		            prev.add(x);
		        } else {
		            next.add(prev);
		            prev = x;
		        }
		        max = Math.max(max, prev.getCount());
		    }
		    sb.append(max).append("\n");
		    next.add(prev);
		    PriorityQueue<Work> tmp = next;
		    next = queue;
		    queue = tmp;
		}
		System.out.print(sb);
   }
   
   static class Work implements Comparable<Work> {
       long start;
       long end;
       
       public Work(long start, long end) {
           this.start = start;
           this.end = end;
       }
       
       public int compareTo(Work another) {
           if (start == another.start) {
               if (end == another.end) {
                   return 0;
               } else if (end < another.end) {
                   return -1;
               } else {
                   return 1;
               }
           } else {
               if (start == another.start) {
                   return 0;
               } else if (start < another.start) {
                   return -1;
               } else {
                   return 1;
               }
           }
       }
       
       public long getCount() {
           return end - start + 1;
       }
       
       public void add(Work another) {
           start = Math.min(start, another.start);
           end = Math.max(end, another.end);
       }
       
       public String toString() {
           return "start:" + start + " end:" + end;
       }
   }
 }