def solve(D, Q, Qs):
    taskrange = []
    result = []
    for q in Qs:
        t = [int(ql) for ql in q.split(" ")]
        merged = False

        while(True):
            merging = False
            for i, task in enumerate(taskrange):
                if t == task: continue
                if task[0] <= t[1] <= task[1] + 1 or task[0] <= t[0] <= task[1]  + 1 or \
                    t[0] <= task[1] <= t[1]  + 1 or t[0] <= task[0] <= t[1]  + 1:
                    taskrange[i] = [min(task[0], t[0]), max(task[1], t[1])]
                    t = task
                    merging = True
                    merged = True
            if not merging:
                break

        if not merged:
            taskrange.append(t)

        result.append(max([t[1] - t[0] + 1for t in taskrange]))

    return result

if __name__ == "__main__":
    D, Q = tuple([int(c) for c in input().split(" ")])
    print("\n".join([str(a) for a in solve(D, Q, [input() for _ in range(0, Q)])]))