#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>

using namespace std;

namespace model{
	const int N = 1e6+7,P=998244353;
	int read()
	{
		int a = 0,x = 1;char ch = getchar();
		while(ch > '9' || ch < '0') {if(ch == '-') x = -1;ch = getchar();}
		while(ch >= '0' && ch <= '9'){a = a*10 + ch-'0';ch = getchar();}
		return a*x;
	}
	int fpow(int a,int x,int p) 
	{
		if(x == 1) return a;
		if(x == 0) return 1;
		int t = fpow(a,x>>1,p);
		if(x&1) return t*t%p*a%p;
		return t*t%p;
	}
	void Mod(int &a) {if(a >= P) a %= P;}
}

using model::read;
using model::N;
int n,a[N];

void solve()
{
	n = read();
	for(int i = 1;i <= n;i ++) a[i] = read();
	sort(a+1,a+1+n);int len = unique(a+1,a+1+n) - a-1;
	if(n == len) puts("Yes");
	else puts("No");
}

int main()
{
	int t = 1;
	while(t --) solve();
}
#include <bits/stdc++.h>

using namespace std;

#define ar array
#define ll long long

const int MAX_N = 1e5 + 1;
const ll MOD = 1e9 + 7;
const ll INF = 1e9;

void solve() {
    int n;
    cin >> n;
    int arr[n], check[n+1];
    memset(check, 0, sizeof(check));
    for(int i=0; i<n; i++){
        cin >> arr[i];
        check[arr[i]]++;
    }

    for(int i=1; i<=n; i++){
        if(check[i]!=1){
            cout << "No\n";
            return;
        }
    }
    cout << "Yes\n";
    return;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int tc = 1;
    // cin >> tc;
    for (int t = 1; t <= tc; t++) {
        // cout << "Case #" << t  << ": ";
        solve();
    }
}