# include "bits/stdc++.h"
using namespace std;
using LL = long long;
using ULL = unsigned long long;
const double PI = acos(-1);
template<class T>constexpr T INF() { return ::std::numeric_limits<T>::max(); }
template<class T>constexpr T HINF() { return INF<T>() / 2; }
template <typename T_char>T_char TL(T_char cX) { return tolower(cX); };
template <typename T_char>T_char TU(T_char cX) { return toupper(cX); };
typedef pair<LL, LL> pii;
const int vy[] = { -1, -1, -1, 0, 1, 1, 1, 0 }, vx[] = { -1, 0, 1, 1, 1, 0, -1, -1 };
const int dx[4] = { 0,1,0,-1 }, dy[4] = { 1,0,-1,0 };
int popcnt(unsigned long long n) { int cnt = 0; for (int i = 0; i < 64; i++)if ((n >> i) & 1)cnt++; return cnt; }
int d_sum(LL n) { int ret = 0; while (n > 0) { ret += n % 10; n /= 10; }return ret; }
int d_cnt(LL n) { int ret = 0; while (n > 0) { ret++; n /= 10; }return ret; }
LL gcd(LL a, LL b) { if (b == 0)return a; return gcd(b, a%b); };
LL lcm(LL a, LL b) { LL g = gcd(a, b); return a / g*b; };
# define ALL(qpqpq)           (qpqpq).begin(),(qpqpq).end()
# define UNIQUE(wpwpw)        sort(ALL((wpwpw)));(wpwpw).erase(unique(ALL((wpwpw))),(wpwpw).end())
# define LOWER(epepe)         transform(ALL((epepe)),(epepe).begin(),TL<char>)
# define UPPER(rprpr)         transform(ALL((rprpr)),(rprpr).begin(),TU<char>)
# define FOR(i,tptpt,ypypy)   for(LL i=(tptpt);i<(ypypy);i++)
# define REP(i,upupu)         FOR(i,0,upupu)
# define INIT                 std::ios::sync_with_stdio(false);std::cin.tie(0)

int n, m;
int l[2020], r[2020];
bool used[2020];

int main(){
    INIT;
    cin >> n >> m;
    REP(i, n){
        cin >> l[i] >> r[i];
    }
    int left = 0;
    REP(i, n){
        int num = -1;
        REP(j, n){
            if(!used[j]){
                if(m - 1 - r[j] < l[j]){
                    l[j] = m - 1 - l[j];
                    r[j] = m - 1 - r[j];
                    swap(l[j], r[j]);
                }
                if(left > l[j]){
                    l[j] = m - 1 - l[j];
                    r[j] = m - 1 - r[j];
                    swap(l[j], r[j]);
                }
                if(left > l[j]){
                    cout << "NO" << endl;
                    return 0;
                }
                if(num == -1||l[j] < l[num])num = j;
            }
        }
        left = r[num] + 1;
        used[num] = true;
    }
    cout << "YES" << endl;
}