#include <iostream>
using namespace std;

long long A, B, C, D;
unsigned long long VA, VB, VC, VD;
int ty1, ty2;

int sgn(long long val) {
	if (val < 0LL) return -1;
	if (val > 0LL) return 1;
	return 0;
}
int sgn2(long long A, long long B) {
	// A÷B の正負を判定
	if (sgn(A) == 0) return 0;
	if (sgn(A) + sgn(B) == 0) return -1;
	return 1;
}

int main() {
	cin >> A >> B >> C >> D;
	VA = abs(A); VB = abs(B);
	VC = abs(C); VD = abs(D);
	ty1 = sgn2(A, B);
	ty2 = sgn2(C, D);

	// 場合分け
	if (ty1 < ty2) { cout << "Yes" << endl; }
	else if (ty1 > ty2) { cout << "No" << endl; }
	else if (ty1 == 0) { cout << "No" << endl; }
	else if (ty1 == -1) {
		if (VA * VD > VB * VC) cout << "Yes" << endl;
		else cout << "No" << endl;
	}
	else if (ty1 == 1) {
		if (VA * VD < VB * VC) cout << "Yes" << endl;
		else cout << "No" << endl;
	}
	return 0;
}