#include <bits/stdc++.h>
#define ll long long
using namespace std;
//reverse(s.begin(),s.end())
ll gcd(ll a,ll b){
    ll s=1,c;
    while(a&&b){
        if((~a&1)&&(~b&1))
            a>>=1,b>>=1,s<<=1;
        else if(~a&1)a>>=1;
        else if(~b&1)b>>=1;
        else if(a>b)a=a-b;
        else c=b-a,b=a,a=c;
    }
    if(!a)return b*s;
    if(!b)return a*s;
}
int main(){
	ll n=1;cin>>n;
	ll k;ll ans = 6987268688401;
	cout<<ans;
}

/* Basic Inclusion */
#define _GLIBCXX_DEBUG
#include <bits/stdc++.h>
using namespace std;
/* definition */
#define rep(i, N) for (ll i = 0; i < (ll)(N); i++)
#define repp(i, N) for (ll i = 1; i <= (ll)(N); i++)
#define per(i, N) for (ll i = (ll)(N)-1; i >= 0; i--)
#define pper(i, N) for (ll i = (ll)(N); i > 0; i--)
#define pub(n) push_back(n)
#define pob(n) pop_back(n)
#define all(v) (v).begin(), (v).end()
#define grsort(v) sort((v).begin, (v).end, greater<>())
#define setpre(i) cout << fixed << setprecision((ll)(i))
#define tstr to_string
#define bpop(n) __builtin_popcount(n)
/* I am lazy XD */
#define co(ans) cout << (ans)
#define out(ans) << (ans)
#define margin << " "
#define fin << endl
#define enter cout << endl
/* Common */
#define ll long long
#define dd double
#define cc char
#define ss string
ll cin_long_long(){ ll value; cin >> value; return value; }
dd cin_double(){ dd value; cin >> value; return value; }
cc cin_char(){ cc value; cin >> value; return value; }
ss cin_string(){ ss value; cin >> value; return value; }
#define cinl cin_long_long()
#define cind cin_double()
#define cinc cin_char()
#define cins cin_string()
#define mod 1000000007
#define inf 9223372036854775807
#define minf -9223372036854775807
#define pi 3.1415926535897932384626433832795028
ll bit(ll N){ return (1 << N); }
/* template functions */
ll ctol(char c){
   switch (c){
   case '1': return 1; break;
   case '2': return 2; break;
   case '3': return 3; break;
   case '4': return 4; break;
   case '5': return 5; break;
   case '6': return 6; break;
   case '7': return 7; break;
   case '8': return 8; break;
   case '9': return 9; break;
   case '0': return 0; break;
   default: return 0; break;
   }
}
/* main functions*/
/* main */
int main(void){
   ll N = cinl; vector<ll> A(N);
   vector<ll> note(N,1);
   rep(i,N) A[i] = cinl;
   rep(i,N){
      if(A[i] <= 0 || A[i] > N){
         co("No") fin;
         return 0;
      }
      else{
         if(note[A[i]-1] == 0){
            co("No") fin;
            return 0;
         }
         note[A[i]-1]=0;
      }
   }
   co("Yes") fin;
}
// /* fin */
