求调，80分

#include<bits/stdc++.h>
using namespace std;
int main(){
	int n,y,s,t,m;
	cin>>n>>y>>s>>t;
	for(int i=1;i<=n;i++)
	{
		int s1=(i-1)*s,s2=i*s;
		m=1;
		if(s1>=y)
			if((s1-y)%t==0||(s2-y)%t==0)m=0;
		if(m)break;
	}
	if(m)cout<<"Yes"<<endl;
	else cout<<"No"<<endl;
	return 0;
}