#include "bits/stdc++.h"
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
/*---------------------DEBUGGING--------------------------------------------*/
void __print(int x) {cerr << x;}
void __print(long x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(unsigned x) {cerr << x;}
void __print(unsigned long x) {cerr << x;}
void __print(unsigned long long x) {cerr << x;}
void __print(float x) {cerr << x;}
void __print(double x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << '\'' << x << '\'';}
void __print(const char *x) {cerr << '\"' << x << '\"';}
void __print(const string &x) {cerr << '\"' << x << '\"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ','; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? "," : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifndef ONLINE_JUDGE
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif
/*-------------------------------------------------------------------------------------*/
#define pb push_back
#define ll long long
#define pii pair<int,int>
#define pcc pair<char,char>
#define F first
#define S second
#define int long long
#define pi 3.141592653589793238462643383279502
#define M 1000000007 //998244353
#define rep(i,a,n) for(int i=a;i<n;i++)
#define INF 1e18
#define N 100005
#define vi vector<int>
#define all(v) v.begin(),v.end()
#define endl "\n"
//typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
void solve()
{   int n;
    cin>>n;
    vi a(n);
    rep(i,0,n)cin>>a[i];
    sort(all(a));
    bool f = true;
    for(int i=0;i<n;i++)
    {
        if(a[i] != (i+1))f=false;
    }
    if(f)cout<<"Yes"<<endl;
    else cout<<"No"<<endl;
}
signed main()
{
   ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0);
   int tests;
   tests=1;
   //cin>>tests;
   for(int i=0;i<tests;i++)
   {
       solve();
   }
}


#include<bits/stdc++.h>
using namespace std;
int n;
int chk[100001];
int main(){
    scanf("%d" , &n);
    for(int i = 0; i<n;i++){
        int tmp;
        scanf("%d" , &tmp);
        if(chk[tmp]){
            printf("No");
            return 0;
        }
        chk[tmp]=1;
    }
    printf("Yes");
}

