#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
#define ll long long
#define OO 2'000'000'000
#define ull unsigned long long
#define nl '\n'
#define sz(x) (ll)(x.size())
#define all(x) x.begin(),x.end()
#define rall(s)  s.rbegin(), s.rend()
#define getline(s) getline(cin>>ws,s)
#define ceill(n, m) (((n) / (m)) + ((n) % (m) ? 1 : 0))
#define pi  3.141592653589793
#define ordered_set tree<int, null_type,less<int>, rb_tree_tag,tree_order_statistics_node_update>
#define multi_ordered_set tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>


void Fast_IO(){
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
// freopen("filename.in", "r", stdin);
// freopen("filename.txt", "w", stdout);
#ifndef ONLINE_JUDGE
    freopen("input.txt", "r", stdin), freopen("output.txt", "w", stdout);
#endif
}




int dx[] = { 2, 1, -1, -2, -2, -1, 1, 2 };
int dy[] = { 1, 2, 2, 1, -1, -2, -2, -1 };




void solve() {
    ll n;
    cin >> n;
    vector<ll> v(n), reorder(n);

    for (auto &i: v) cin >> i;
    if (n == 1) return cout << "YES", void();
    if (n == 2) {
        if (v[0] == v[1]) return cout << "NO", void();
        return cout << "YES", void();
    }
    sort(rall(v));
    for (int i = 0; i < n; i += 2) {
        reorder[i] = v.back();
        v.pop_back();
    }
    for (int i = 1; i < n; i += 2) {
        reorder[i] = v.back();
        v.pop_back();
    }


    for (int i = 1; i < n - 1; i++) {
        if (i % 2) {
            if (reorder[i] > reorder[i - 1] and reorder[i] > reorder[i + 1]) continue;
            else return cout << "NO", void();
        } else {
            if (reorder[i] < reorder[i - 1] and reorder[i] < reorder[i + 1]) continue;
            else return cout << "NO", void();
        }
    }
    cout << "YES";

}

int main(){
    Fast_IO();
    int t =1;
//cin>>t;
    while(t--){
        solve();
    }
    return 0;
}