#pragma GCC optimize ("O3")
#pragma GCC target ("avx")
#include "bits/stdc++.h" // define macro "/D__MAI"

using namespace std;
typedef unsigned int uint;
typedef long long int ll;
typedef unsigned long long int ull;

#define debugv(v) printf("L%d %s => ",__LINE__,#v);for(auto e:v){cout<<e<<" ";}cout<<endl;
#define debugm(m) printf("L%d %s is..\n",__LINE__,#m);for(auto v:m){for(auto e:v){cout<<e<<" ";}cout<<endl;}
#define debuga(m,w) printf("L%d %s is => ",__LINE__,#m);for(int x=0;x<(w);x++){cout<<(m)[x]<<" ";}cout<<endl;
#define debugaa(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[x][y]<<" ";}cout<<endl;}
#define debugaar(m,w,h) printf("L%d %s is..\n",__LINE__,#m);for(int y=0;y<(h);y++){for(int x=0;x<(w);x++){cout<<(m)[y][x]<<" ";}cout<<endl;}
#define ALL(v) (v).begin(),(v).end()
#define repeat(l) for(auto cnt=0;cnt<(l);++cnt)
#define upto(l,r) for(auto cnt=l;cnt<=r;++cnt)
#define downto(r,l) for(auti cnt=r;cnt>=l;--cnt)
#define BIGINT 0x7FFFFFFF
#define MD 1000000007ll
#define PI 3.1415926535897932384626433832795

#define TIME chrono::system_clock::now()
#define MILLISEC(t) (chrono::duration_cast<chrono::milliseconds>(t).count())
namespace {
    std::chrono::system_clock::time_point ttt;
    void tic() { ttt = TIME; }
    void toc() { fprintf(stderr, "TIME : %lldms\n", MILLISEC(TIME - ttt)); }
    std::chrono::system_clock::time_point tle = TIME;
#ifdef __MAI
    void safe_tle(int msec) { assert(MILLISEC(TIME - tle) < msec); }
#else
#define safe_tle(k) ;
#endif
}

#ifdef __MAI //_getchar_nolock
#define getchar_unlocked getchar
#endif
namespace {
    class MaiScanner {
    public:
        template<typename T>
        void input_integer(T& var) {
            var = 0;
            T sign = 1;
            int cc = getchar_unlocked();
            for (; cc<'0' || '9'<cc; cc = getchar_unlocked())
                if (cc == '-') sign = -1;
            for (; '0' <= cc&&cc <= '9'; cc = getchar_unlocked())
                var = (var << 3) + (var << 1) + cc - '0';
            var = var*sign;
        }
        inline int c() { return getchar_unlocked(); }
        inline MaiScanner& operator>>(int& var) {
            input_integer<int>(var);
            return *this;
        }
        inline MaiScanner& operator>>(long long& var) {
            input_integer<long long>(var);
            return *this;
        }
    };
}
MaiScanner scanner;



class GraphE {
public:
    size_t n;
    struct Edge {
        int u, v;
        Edge(int from = 0, int to = 0) :u(from), v(to) {}

        int to(int _v) { return _v == v ? u : v; }

    };
    vector<vector<int>> vertex_to;
    vector<Edge> edge;

    GraphE(int n, int m = 5010) :n(n), vertex_to(n) { edge.reserve(m); }

    void connect(int from, int to) {
        vertex_to[from].push_back(edge.size()); // toto
        vertex_to[to].push_back(edge.size()); // fromfrom
        edge.emplace_back(from, to);
    }
    size_t degree(int v) {
        return vertex_to[v].size();
    }
    void resize(size_t _n) {
        n = _n;
        vertex_to.resize(_n);
    }
};


int width, height;
int m, n, kei;

int imos[100010];

int main() {
    int i, j, k;
    int x, y, z, a, b, c;


    scanner >> n >> m;

    repeat(m) {
        scanner >> x >> y;
        ++imos[x];
        --imos[y];
    }

    a = 0;
    upto(1, n + 1) {
        a += imos[cnt];
        if (a % 2) {
            cout << "NO" << endl;
            return 0;
        }
    }
    cout << "YES" << endl;

    return 0;
}

Measured memory_bytes: 640