#include<bits/stdc++.h>
using namespace std;
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rrep(i, k, n) for (int i = k; i < (int)(n); i++)
#define repd(i, n) for (int i = n-1; i >= 0; i--)
#define rrepd(i, k, n) for (int i = n-1; i >= (int)(k); i--)
#define all(x) (x).begin(),(x).end()
#define chmax(x,y) x=max(x,y)
#define chmin(x,y) x=min(x,y)
#define F first //pairの一つ目の要素  //遅延セグ木使うときは注意
#define S second //pairの二つ目の要素  //遅延セグ木使うときは注意
#define PB push_back //挿入
#define MP make_pair //pairのコンストラクタ
//V,Pは大文字i,l,bは小文字
using ll = long long;
using Vi = vector<int>;
using VVi = vector<Vi>;
using Vl = vector<ll>;
using VVl = vector<Vl>;
using Vb = vector<bool>;
using VVb = vector<Vb>;
using P = pair<int,int>;
using Pl = pair<ll, ll>;
using Vs = vector<string>;
const ll mod = 1000000007;
const ll inf = 1000000000000000000;//10の18乗
#define yn {puts("Yes");}else{puts("No");}
#define dame { puts("-1"); return 0;}

int main() {
    ll n;
    cin >> n;
    Vl v(n);
    rep(i,n) cin >> v[i];
    sort(all(v));
    ll ok=1;
    rep(i,n) if(v[i]!=i+1) ok=0;
    if(ok) yn;
}

#include<bits/stdc++.h>

using namespace std;

int main(){
    int a;
    cin>>a;
    priority_queue<int> pq;
    for(int i=0;i<a;i++){
        int c;
        cin>>c;
        pq.push(c);
    }
    while(pq.size()){
        if(pq.top()!=a){
            cout<<"No";
            return 0;
        }
        pq.pop();
        a--;
    }
    cout<<"Yes";
    return 0;
}