using System;
using static System.Console;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static int NN => int.Parse(ReadLine());
    static int[] NList => ReadLine().Split().Select(int.Parse).ToArray();
    static void Main()
    {
        var c = NList;
        var (n, m) = (c[0], c[1]);
        var list = new int[n];
        for (var i = 0; i < m; ++i)
        {
            c = NList;
            ++list[c[1] - 1];
        }
        WriteLine(list.Count(li => li == 0));
    }
}