#include <iostream>
#include <cstdio>
#include <cstring>
#include <stack>
using namespace std;
const int N = 2010;
const int M = 2000010;
int n , m ;

int st[N] , top ;
bool mark[N];
int eh[N] , et[M] , nxt[M] , tot ;

void init()
{
    tot = 0 ;
    memset( eh , -1 , sizeof eh );
    memset( mark , false , sizeof mark );
}

void addedge( int u , int v ){
    et[tot] = v , nxt[tot] = eh[u] , eh[u] = tot ++ ;
    et[tot] = u , nxt[tot] = eh[v] , eh[v] = tot ++ ;
}

bool dfs( int u )
{
    if( mark[u] ) return true;
    if( mark[u^1] ) return false;
    mark[u] = true ;
    st[top++] = u ;
    for( int i = eh[u] ; ~i ; i = nxt[i] ){
        int v = et[i];
        if( !dfs(v^1) ) return false;
    }
    return true;
}

bool solve()
{
    for(int i = 0 ; i < 2 * n ; i += 2 ){
        if( !mark[i] && !mark[i+1] ){
            top = 0 ;
            if( !dfs(i) ){
                while( top > 0 ) mark[ st[--top] ] = false;
                if( !dfs(i+1) ) return false ;
            }
        }
    }
    return true;
}

int main()
{
    #ifdef LOCAL
        freopen("in.txt","r",stdin);
    #endif // LOCAL
    ios::sync_with_stdio(0);
    int id1 , id2 , x1 , x2 ;
    while( cin >> n >> m  ){
        init();
        for( int i = 0 ; i < m ; ++i ){
            cin >> id1 >> id2 >> x1 >> x2 ;
            addedge( 2*id1 + x1 , 2*id2 + x2 );
        }
        if( solve() ) cout << "YES" << endl;
        else cout << "NO" << endl;
    }
}