#include <iostream>
#include <cmath>
using namespace std;

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

int sgn(long long x) {
	if (x > 0LL) return 1;
	if (x == 0LL) return 0;
	return -1;
}
int getSign(long long a, long long b) {
	// a/b の正負を判定する
	if (a == 0) return 0;
	if (sgn(a) == sgn(b)) return 1;
	return -1;
}

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

	bool Answer = false;
	if (sgn(B) == sgn(D)) {
		int sgnLeft = getSign(A, B);
		int sgnRight = getSign(C, D);
		if (sgnLeft < sgnRight) Answer = true;
		else if (sgnLeft > sgnRight) Answer = false;
		else if (sgnLeft == 1 && VA * VD < VB * VC) Answer = true;
		else if (sgnLeft == -1 && VA * VD > VB * VC) Answer = true;
	}
	if (sgn(B) != sgn(D)) {
		int sgnLeft = getSign(A, B);
		int sgnRight = getSign(C, D);
		if (sgnLeft < sgnRight) Answer = true;
		else if (sgnLeft > sgnRight) Answer = false;
		else if (sgnLeft == 1 && VA * VD > VB * VC) Answer = true;
		else if (sgnLeft == -1 && VA * VD < VB * VC) Answer = true;
	}

	if (Answer == true) cout << "Yes" << endl;
	else cout << "No" << endl;
	return 0;
}