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();
		TreeSet<Work> set = new TreeSet<>();
		StringBuilder sb = new StringBuilder();
		long max = 0;
		for (int i = 0; i < q; i++) {
		    Work tmp = new Work(sc.nextLong(), sc.nextLong());
		    while (true) {
		        Work before = set.floor(tmp);
		        if (before == null || before.end < tmp.start - 1) {
		            break;
		        }
		        tmp.add(before);
		        set.remove(before);
		    }
		    while (true) {
		        Work after = set.ceiling(tmp);
		        if (after == null || tmp.end < after.start - 1) {
		            break;
		        }
		        tmp.add(after);
		        set.remove(after);
		    }
		    max = Math.max(max, tmp.getCount());
		    set.add(tmp);
		    sb.append(max).append("\n");
		}
		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 int hashCode() {
           return (int)start;
       }
       
       public boolean equals(Object o) {
           Work another = (Work) o;
           return start == another.start && end == another.end;
       }
       
       public String toString() {
           return "start:" + start + " end:" + end;
       }
   }
 }