#include<iostream> #include<vector> #include<algorithm> typedef long long ll; using namespace std; int main(void){ ll l,r,m,k; cin>>l>>r>>m>>k; if(k==0){ cout<<"Yes"<<endl; return 0; } if(m==1){ cout<<"Yes"<<endl; return 0; } if(l==0){ cout<<"Yes"<<endl; return 0; } if(r-l+1>=m){ cout<<"Yes"<<endl; return 0; } if((l<=m)&&(m<=r)){ cout<<"Yes"<<endl; return 0; } ll mi = k*l; ll ma = k*r; if((mi<=m)&&(m<=ma)){ cout<<"Yes"<<endl; return 0; } ll x = mi/m; ll y = ma/m; if(ma%m!=0)y++; if(y-x>1)cout<<"Yes"; else cout<<"No"; return 0; }