#include <bits/stdc++.h>

using namespace std;

#define ALL(x) x.begin(), x.end()
#define MP make_pair

using ll = long long;
using pii = pair<int, int>;
using pll = pair<ll, ll>;

int main() {
#ifndef LOCAL
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
#endif

    int n = 0;
    cin >> n;
    set<int> st;
    for (int i = 0; i < n; i++) {
        st.insert(i + 1);
    }
    for (int i = 0; i < n; i++) {
        int x = 0;
        cin >> x;
        st.erase(x);
    }
    if (st.size()) {
        cout << "No" << '\n';
    } else {
        cout << "Yes" << '\n';
    }

    return 0;
}
/**
 *  created: 2021/06/13  20:01:23
 *  compile: g++ sol.cpp -o sol.out -g -std=c++17 -Wall -Wextra -Wshadow -fsanitize=undefined -fsanitize=address -D_GLIBCXX_DEBUG -DLOCAL
**/

#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/detail/standard_policies.hpp>
using namespace __gnu_pbds;
using namespace std;


#define LETS_GET_SCHWIFTY ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);  
#define ff              first
#define ss              second
#define int             long long
#define ll              long long
#define pb              push_back
#define pii             pair<int,int>
#define vi              vector<int>
#define pqb             priority_queue<int>
#define pqs             priority_queue<int,vi,greater<int> >
#define setbits(x)      __builtin_popcountll(x)
#define zerobits(x)      __builtin_ctzll(x)
#define mod             998244353
#define inf             1e18
#define ps(x,y)         fixed<<setprecision(y)<<x
#define vpii            vector<pair<int,int> >
#define all(x)          x.begin(),x.end()
#define matrixprint(arr,a,b,c,d) for(int i=a;i<=c;i++){for(int j=b;j<=d;j++){cout<<arr[i][j]<<" ";}cout<<"\n";}
#define show(arr,x,y)   for(int i=x;i<=y;i++){cout<<arr[i]<<" ";}cout<<"\n"
#define sz(x)           (int)x.size()
#define db(x)           cout<<x<<"\n";

typedef tree<
int,
null_type,
less<int>,
rb_tree_tag,
tree_order_statistics_node_update>
ordered_set;

//insert,find_by_order,order_of_key,lower_bound,upper_bound;

#define TRACE
#ifdef TRACE
#define deb(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
    cout << name << " : " << arg1 << std::endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
    const char* comma = strchr(names + 1, ','); cout.write(names, comma - names) << " : " << arg1 << " | "; __f(comma + 1, args...);
}
#else
#define deb(...)
#endif

  
//////////////////////////////code//////////////////////////////

const int N = 200;



void solve()
{

      int n;
      cin >> n;

      vi cnt(n + 1);

      for(int i = 0;i < n; i++)
      {
            int d;
            cin >> d;
            cnt[d]++;
      }

      for(int i = 1;i <= n ;i++)
      {
            if(cnt[i] != 1)
            {
                db("No")
                return;
            }
      }

      db("Yes")

}

int32_t main()
{   

    LETS_GET_SCHWIFTY;

     #ifndef ONLINE_JUDGE
     freopen("INP.txt", "r", stdin);
     freopen("out.txt", "w", stdout);
     #endif  


    int t = 1;
   //cin >> t;

    while (t--)
        solve();

}

// check out for following mistakes-
// if using pb operation on vector and then trying to access index..check if sizeof that vec could remain 0 only
// is using prime sieve make sure it fits
// when using factorial template or combinatorics make sure that you edit fillfac fun values and array values

