#nullable enable

#region
var (_input, _iter) = (Array.Empty<string>(), 0);
T I<T>() where T : IParsable<T>
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Split(' '), 0);
    return T.Parse(_input[_iter++], null);
}
#endregion

static T[] Range<T>(int n, Func<T> F) => Enumerable.Range(0, n).Select(_ => F()).ToArray();

var n = I<int>();
var m = I<int>();
var az = Range(m, I<int>);
var ans = new List<string>();
var first = -1;
var last = int.MinValue;
var len = 0;
foreach (var a in az)
{
    if (a == last + 1)
    {
        last = a;
        len++;
        continue;
    }
    if (len > 0) ans.Add(first + " " + len);
    first = last = a;
    len = 1;
}
if (len > 0) ans.Add(first + " " + len);
Console.WriteLine(ans.Count);
Console.WriteLine(string.Join(Environment.NewLine, ans));