import sys


def input(): return sys.stdin.readline().rstrip('\n')


def main():
    n, m = map(int, input().split())
    *a, = map(int, input().split())

    ans = []
    arr = []
    for i in a:
        if not arr or arr[-1] + 1 == i:
            arr.append(i)
        else:
            ans.append((arr[0], len(arr)))
            arr = [i]

    ans.append((arr[0], len(arr)))

    print(len(ans))
    for k, v in ans:
        print(k, v)


if __name__ == '__main__':
    main()