#include <iostream>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <numeric>
#include <bitset>
#include <cmath>

static const int MOD = 1000000007;
using ll = long long;
using u32 = unsigned;
using u64 = unsigned long long;
using namespace std;

template<class T> constexpr T INF = ::numeric_limits<T>::max()/32*15+208;

int main() {
    ll l, r, m, k;
    cin >> l >> r >> m >> k;
    if((l*k-1)/m != r*k/m || l*k%m == 0) puts("Yes");
    else puts("No");
    return 0;
}