/*
    author: Salam_35
    Created at :

*/

#include <bits/stdc++.h>
using namespace std;

#define ll long long int
#define pb push_back
#define sc(n) scanf("%d",&n)
#define Max 100005
#define scan(n) scanf("%lld",&n)
#define pi acos(-1.0)
#define _fastio  ios_base:: sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define ALL(x) x.begin(),x.end()
#define sci(n) scanf("%d",&n);
#define scl(n) scanf("%lld",&n);
#define load(array,size)  for(ll i=0 ; i<size ; i++) cin>>array[i] ;
#define load1(array,size)  for(ll i=1 ; i<=size ; i++) cin>>array[i] ;
#define INF	1LL<<19
#define pll pair<ll,ll>
#define mst(arr,value) memset(arr,value,sizeof(arr));
#define tst() int t;cin >> t;while(t--)
#define Mod 100000007
#define YES cout<<"Yes"<<endl;
#define NO cout<<"No"<<endl;
#define endl '\n'
//void inversemod(ll n, ll mod, ll invmod[],ll MOD){for(int i=2; i<=n; ++i) invmod[i]=MOD-MOD/i*invmod[MOD%i]%MOD;}
//void bigmod( ll a, ll b ,ll mod){ll r = 1;a = a%mod;while(b){if( b%2 ) r = (r*a)%mod;b = b/2;a = (a*a)%mod; }return (ll)r;}

typedef vector<ll>vec;
typedef pair<ll,ll> pii;
typedef map<ll,ll>mpll;
typedef set<ll>seet;

int main()
{
    int a,b,c,d;
    cin>> a>> b>>c>>d;
    int i=0;
    // while(1)
    // {
    //     if(i%2==0)
    //     {
    //         c-=b;
    //     }
    //     else if(i%2==1)a-=d;
    //     if(a<=0){
    //         cout<<"No"<<endl;
    //         return 0;
    //     }
    //     if(c<=0){
    //         cout<<"No"<<endl;
    //         return 0;
    //     }
    //     i++;
    //     cout<<a<<' '<<c<<endl;
    // }
    int dif=a-c;
    if(dif<d)cout<<"No"<<endl;
    else cout<<"Yes"<<endl;
    
}
