#include<bits/stdc++.h>
using namespace std;
#define IOS ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define ll long long 
#define ull unsigned long long 
#define endl "\n"
#define loop(n) for(int i = 0; i<n; ++i)
const int N = 1e3+5; 
int n, freq[N], x;
bool permutation = true;
int main()
{
    IOS;
    cin >> n;
    loop(n)
    {
        cin >> x;
        freq[x]++;
    }
    for(int i = 1; i<=n; ++i)
    {
        if(freq[i] != 1)
        {
            permutation = false;
            break;
        }
    }
    if(!permutation) return cout << "No" << endl, 0;
    cout << "Yes" << endl;
    return 0;
}
#include <bits/stdc++.h>
using namespace std;

int main() {
    int N;
    cin >> N;
    set<int> S;
    for(int i = 0;i<N;i++){
        int a;
        cin >> a;
        S.insert(a);
    }

    if(N == S.size()) cout << "Yes" <<endl;
    else cout << "No" <<endl;
}