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

using ll = long long;
using VI = vector<int>;
using P = pair<int, int>;

#define REP(i, n) for (int i = 0; i < (int)(n); i++)
#define FOR(i, a, b) for (ll i = a; i < (ll)(b); i++)
#define ALL(a) (a).begin(),(a).end()

constexpr int INF = 1001001001;
constexpr ll LINF = 1001001001001001001ll;
constexpr int DX[] = {1, 0, -1, 0};
constexpr int DY[] = {0, 1, 0, -1};

template< typename T1, typename T2>
inline bool chmax(T1 &a, T2 b) {return a < b && (a = b, true); }
template< typename T1, typename T2>
inline bool chmin(T1 &a, T2 b) {return a > b && (a = b, true); }

const ll MOD = 1000000007;

int main() {
    int N, a, b, c;
    cin >> N >> a >> b >> c;
    string ans = "No";
    if (a < b && b <= c) ans = "Yes";
    if (a < c && c <= b) ans = "Yes";
    if (b <= c && c < a) ans = "Yes";
    if (c <= b && b < a) ans = "Yes";
    cout << ans << endl;
}