using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using static System.Math;
using System.Text;
using System.Threading;
using System.Globalization;
using System.Runtime.CompilerServices;
using Library;

namespace Program
{
    public static class AGC014B
    {
        static public int numberOfRandomCases = 0;
        static public void MakeTestCase(List<string> _input, List<string> _output, ref Func<string[], bool> _outputChecker)
        {
        }
        static public void Solve()
        {
            var N = NN;
            var M = NN;
            var ab = Repeat(0, M).Select(_ => new { a = NN - 1, b = NN - 1 }).ToArray();
            var seg = new LIB_DualSegTree<long>(N, 0, (x, y) => x + y);
            foreach (var item in ab)
            {
                if (item.a < item.b) seg.Update(item.a, item.b, 1);
                else seg.Update(item.b, item.a, 1);
            }
            for (var i = 0; i < N; i++)
            {
                if (seg[i] % 2 == 1)
                {
                    Console.WriteLine("NO");
                    return;
                }
            }
            Console.WriteLine("YES");
        }
        static class Console_
        {
            static Queue<string> param = new Queue<string>();
            public static string NextString() { if (param.Count == 0) foreach (var item in Console.ReadLine().Split(' ')) param.Enqueue(item); return param.Dequeue(); }
        }
        class Printer : StreamWriter
        {
            public override IFormatProvider FormatProvider { get { return CultureInfo.InvariantCulture; } }
            public Printer(Stream stream) : base(stream, new UTF8Encoding(false, true)) { base.AutoFlush = false; }
            public Printer(Stream stream, Encoding encoding) : base(stream, encoding) { base.AutoFlush = false; }
        }
        static public void Main(string[] args) { if (args.Length == 0) { Console.SetOut(new Printer(Console.OpenStandardOutput())); } var t = new Thread(Solve, 134217728); t.Start(); t.Join(); Console.Out.Flush(); }
        static long NN => long.Parse(Console_.NextString());
        static double ND => double.Parse(Console_.NextString());
        static string NS => Console_.NextString();
        static long[] NNList(long N) => Repeat(0, N).Select(_ => NN).ToArray();
        static double[] NDList(long N) => Repeat(0, N).Select(_ => ND).ToArray();
        static string[] NSList(long N) => Repeat(0, N).Select(_ => NS).ToArray();
        static IEnumerable<T> OrderByRand<T>(this IEnumerable<T> x) => x.OrderBy(_ => xorshift);
        static long Count<T>(this IEnumerable<T> x, Func<T, bool> pred) => Enumerable.Count(x, pred);
        static IEnumerable<T> Repeat<T>(T v, long n) => Enumerable.Repeat<T>(v, (int)n);
        static IEnumerable<int> Range(long s, long c) => Enumerable.Range((int)s, (int)c);
        static uint xorshift { get { _xsi.MoveNext(); return _xsi.Current; } }
        static IEnumerator<uint> _xsi = _xsc();
        static IEnumerator<uint> _xsc() { uint x = 123456789, y = 362436069, z = 521288629, w = (uint)(DateTime.Now.Ticks & 0xffffffff); while (true) { var t = x ^ (x << 11); x = y; y = z; z = w; w = (w ^ (w >> 19)) ^ (t ^ (t >> 8)); yield return w; } }
    }
}
namespace Library {
    class LIB_DualSegTree<T>
    {
        int n, height;
        T ti;
        Func<T, T, T> f;
        T[] dat;
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public LIB_DualSegTree(long _n, T _ti, Func<T, T, T> _f)
        {
            n = 1; height = 0;
            while (n < _n) { n <<= 1; ++height; }
            ti = _ti;
            f = _f;
            dat = Enumerable.Repeat(ti, n << 1).ToArray();
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public LIB_DualSegTree(IEnumerable<T> l, T _ti, Func<T, T, T> _f) : this(l.Count(), _ti, _f)
        {
            var idx = 0;
            foreach (var item in l) dat[n + idx++] = item;
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void Eval(long i)
        {
            if (dat[i].Equals(ti)) return;
            dat[(i << 1) | 0] = f(dat[(i << 1) | 0], dat[i]);
            dat[(i << 1) | 1] = f(dat[(i << 1) | 1], dat[i]);
            dat[i] = ti;
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void Thrust(long i)
        {
            for (var j = height; j > 0; j--) Eval(i >> j);
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        void Thrust(long l, long r)
        {
            if (l == r) { Thrust(l); return; }
            var xor = l ^ r;
            var i = height;
            for (; (xor >> i) != 0; --i) Eval(l >> i);
            for (; i != 0; --i) { Eval(l >> i); Eval(r >> i); }
        }
        [MethodImpl(MethodImplOptions.AggressiveInlining)]
        public void Update(long l, long r, T v)
        {
            if (r < l) throw new Exception();
            Thrust(l += n, r += n - 1);
            for (long li = l, ri = r + 1; li < ri; li >>= 1, ri >>= 1)
            {
                if ((li & 1) == 1) { dat[li] = f(dat[li], v); ++li; }
                if ((ri & 1) == 1) { --ri; dat[ri] = f(dat[ri], v); }
            }
        }
        public T this[long idx]
        {
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            get { Thrust(idx += n); return dat[idx]; }
            [MethodImpl(MethodImplOptions.AggressiveInlining)]
            set { Thrust(idx += n); dat[idx] = value; }
        }
    }
}


Measured memory_bytes: 31556