#include <bits/stdc++.h>
using namespace std;

#define pb push_back
#define mp make_pair
#define f1 first
#define s2 second

#define fastio ios :: sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define debug(x...) cerr << "[" << #x << "]: " << x << "\n";

using ll = long long;
using ld = long double;
using ii = pair<int, int>;
using pl = pair<ll, ll>;

ld const PI = 4*atan((ld)1);

int main()
{
	fastio;

	int n, s, d;
	cin >> n >> s >> d;

	int x, y;
	bool res = false;

	for (int i = 0; i < n; ++i)
	{
		cin >> x >> y;
		if (x < s && y > d) res = true;
	}	
	cout << (res ? "Yes\n" : "No\n");

	return 0;
}

#include <bits/stdc++.h>
using namespace std;
#define reps(i, a, n) for (int i = (a); i < (n); ++i)
#define rep(i, n) reps(i, 0, n)
#define deps(i, a, n) for (int i = (a); i >= (n); --i)
#define dep(i, n) deps(i, n, 0)
#define inf 2147483647
#define int long long

signed main(void)
{
	int v, t, s, d; cin >> v >> t >> s >> d;
	if (v * t > d) cout << "Yes" << endl;
	else if (v * s < d) cout << "Yes" << endl;
	else cout << "No" << endl;
}
