#include<bits/stdc++.h>
using namespace std;
constexpr int M=2005;
int n,t,N,a[M],b[M],lsh[M];
int dis[M],sum[M][M];
vector<tuple<int,int,int>>edge;
int read(){
    int x=0;char ch=getchar();
    while (!isdigit(ch)) ch=getchar();
    while (isdigit(ch)) x=x*10+ch-48,ch=getchar();
    return x;
}
int main(){
    n=read();t=read();
    for (int i=1;i<=n;i++)
        a[i]=read()-1,b[i]=read()-t,
        lsh[++N]=a[i],lsh[++N]=b[i];
    sort(lsh+1,lsh+N+1);N=unique(lsh+1,lsh+N+1)-lsh-1;
    for (int i=1;i<=n;i++)
        a[i]=lower_bound(lsh+1,lsh+N+1,a[i])-lsh,
        b[i]=lower_bound(lsh+1,lsh+N+1,b[i])-lsh;
    auto link=[&](auto u,auto v,auto w){
        edge.emplace_back(u,v,w);
    };
    for (int i=1;i<=N;i++)
        for (int j=i+1;j<=N;j++)
            link(i,j,(lsh[j]-lsh[i]+t-1)/t);
    for (int i=1;i<=n;i++)
        for (int j=1;j<=a[i];j++)
            for (int k=b[i];k<=N;k++)
                sum[j][k]++;
    for (int i=1;i<=N;i++)
        for (int j=i+1;j<=N;j++)
            link(j,i,-sum[i][j]);
    for (int i=1;i<N;i++)
        for (auto [x,y,z]:edge)
            if (dis[x]+z<dis[y])
                dis[y]=dis[x]+z;
    for (auto [x,y,z]:edge)
        if (dis[x]+z<dis[y])
            return puts("no"),0;
    return puts("yes"),0;
}