#include <iostream>
using Int = long long;
int main() {
	int N, S, B;
	std::cin >> N >> S >> B;
	int H[N];
	for (int i = 0; i < N; ++i) std::cin >> H[i];
	bool ans = true;
	Int X = 0;
	for (int i = 0; i < N - 1; ++i) {
		X = std::max(X, H[i] + Int(S * B));
		ans &= X >= H[i + 1];
	}
	std::cout << (ans ? "Yes" : "No") << std::endl;
}