Problem:
Score : 200 points

Problem Statement

Takahashi and Aoki will have a battle using their monsters.

The health and strength of Takahashi's monster are A and B, respectively, and those of Aoki's monster are C and D, respectively.

The two monsters will take turns attacking, in the order Takahashi's, Aoki's, Takahashi's, Aoki's, ...
Here, an attack decreases the opponent's health by the value equal to the attacker's strength.
The monsters keep attacking until the health of one monster becomes 0 or below. The person with the monster whose health becomes 0 or below loses, and the other person wins.

If Takahashi will win, print Yes; if he will lose, print No.

Constraints

1 \leq A,B,C,D \leq 100

All values in input are integers.

Input

Input is given from Standard Input in the following format:

A B C D

Output

If Takahashi will win, print Yes; if he will lose, print No.

Sample Input 1

10 9 10 10

Sample Output 1

No

First, Takahashi's monster attacks Aoki's monster, whose health is now 10-9=1.

Next, Aoki's monster attacks Takahashi's monster, whose health is now 10-10=0.

Takahashi's monster is the first to have 0 or less health, so Takahashi loses.

Sample Input 2

46 4 40 5

Sample Output 2

Yes

Solution in C++ (GCC 9.2.1) (judge verdict: Wrong Answer)

#include<bits/stdc++.h>
using namespace std; 
#define mod 1000000007
#define N 100005
#define ll long long
#define ull unsigned long long
#define loop1(i, j, k, step) for (int i=j; i<k; i+=step)
#define loop(i, j, k) for (int i=j; i<k; i++) 
#define rloop1(i, j, k, step) for (int i=j; i>=k; i-=step)
#define rloop(i, j, k) for(int i=j; i>=k; i--)
#define rep(i, k) for(int i = (0); i < (k); i++ )
#define rrep(i, k) for(int i = k-1; i >= 0; i-- )

#define forall(it, l) for(auto it=l.begin(); it != l.end(); it++)
#define mp make_pair
#define pb push_back
#define pop pop_back
#define F first
#define S second
#define sz(x) (int)(x).size()
#define endl "\n"
#define Max (int)INT_MAX
#define Min (int)INT_MIN
#define MEM(a, b) memset(a, (b), sizeof(a))
#define fast_io ios_base::sync_with_stdio(0), cin.tie(NULL)
typedef vector<int> vi;
typedef pair<int,int> pi;
typedef vector<ll> vl;
typedef pair<ll,ll> pll;


void solve()
{
	int n,i,j,k=0,l,a,b,c,d;
	cin>>a>>b>>c>>d;
	while(a>0 && c>0){
		if(k%2==0)
			c=c-b;
		else
			a=a-d;
		k++;
	}
	if(a==0)
		cout<<"No\n";
	else
		cout<<"Yes\n";
}
int  main() 
{
	auto start=clock();
	fast_io;
    int t=1;
    //cin>>t;
    while(t--)
    	solve();
    auto stop =clock();
    cerr<<"time taken:"<<double(stop-start)/double(CLOCKS_PER_SEC)<<" s"<<endl;
	return 0; 
}