#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define riano_ std::ios::sync_with_stdio(false);std::cin.tie(nullptr)

int main() {
    riano_; //ll ans = 0;
    ll N,a,b,c; cin >> N >> a >> b >> c;
    string ans = "No";
    if((a-c)*(a-b)>0) ans = "Yes";
    cout << ans << endl;
}