#include <bits/stdc++.h>
#include <atcoder/all>
using namespace std;
using namespace atcoder;
using ll = long long;
using pl = std::pair<long long, long long>;
using mint = atcoder::modint1000000007;
//using mint = atcoder::modint998244353;
#define rep(i, srt, end) for (long long i = (srt); i < (long long)(end); i++)
#define all(v) (v).begin(), (v).end()
#define dump(var)  do{ if(debug::enable) { std::cerr << #var << " : "; debug::print(var); } } while(0);
constexpr int di[4] = {1, -1, 0, 0};
constexpr int dj[4] = {0, 0, 1, -1};
constexpr long long inf = 1LL<<60;
template<typename T> inline void chmax(T &a, T b) { a = std::max(a, b); };
template<typename T> inline void chmin(T &a, T b) { a = std::min(a, b); };
template<typename T> void vprint(const std::vector<T>& v) { for(int i = 0; i < v.size(); i++) { std::cout << v[i] << (i == v.size()-1 ? "\n" : " "); } }
template<typename T> void vprintln(const std::vector<T>& v) { for(int i = 0; i < v.size(); i++) { std::cout << v[i] << "\n"; } }
template<int M> void vprint(const std::vector<atcoder::static_modint<M>>& v) { for(int i = 0; i < v.size(); i++) { std::cout << v[i].val() << (i == v.size()-1 ? "\n" : " "); } }
template<int M> void vprintln(const std::vector<atcoder::static_modint<M>>& v) { for(int i = 0; i < v.size(); i++) { std::cout << v[i].val() << "\n"; } }
namespace debug {    
    #if defined(ONLINE_JUDGE)
    const bool enable = false;
    #else
    const bool enable = true;
    #endif
    template<typename T> void push(const T& e) { std::cerr << e; }
    template<int M> void push(const atcoder::static_modint<M>& e) { std::cerr << e.val(); }
    template<typename T1, typename T2> void push(const std::pair<T1, T2>& e) { std::cerr << "("; push(e.first); std::cerr << ","; push(e.second); std::cerr << ")"; }   
    template<typename T1, typename T2, typename T3> void push(const std::tuple<T1, T2, T3>& e) { std::cerr << "("; push(get<0>(e)); std::cerr << ","; push(get<1>(e)); std::cerr << ","; push(get<2>(e)); std::cerr << ")"; }   
    template<typename T> void print(const T& e) { push(e); std::cerr << "\n"; }
    template<typename T> void print(const std::vector<T>& v) { for(int i = 0; i < v.size(); i++) { push(v[i]); std::cerr << " "; } std::cerr << "\n"; }
    template<typename T> void print(const std::vector<std::vector<T>>& v) { std::cerr << "\n"; for(int i = 0; i < v.size(); i++) { std::cerr << i << ": "; print(v[i]); } }
};

void solve() {
    ll n, a, b, c;
    cin >> n >> a >> b >> c;
    vector v = {a, b, c};
    sort(all(v));
    bool ok = false;
    if(v.front() == a && v.back() == c) ok = true;
    if(v.front() == c && v.back() == a) ok = true;
    if(a == c) ok = false;
    cout << (ok ? "Yes" : "No") << endl;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    solve();
    return 0;
}