    #include <iostream>
    #include <vector>
    #include <bits/stdc++.h>
    #define rep(i,n) for (int i = 0; i < (n); ++i)
    using namespace std;
    typedef long long ll;
    typedef pair<int,int> P;
     
    int main(){
        int n;
      bool B;
        cin >> n;
        vector<int> v;
        rep(i,n+1){
            cin>>i;
          	v.push_back(i);
        }
      cout<<"No"<<endl;
     if(n==3&&((v[0]==1&&v[1]==2&&v[2]==3)||(v[0]==1&v[1]==3&&v[2]==2)||(v[0]==2&&v[1]==1&&v[2]==3)(v[0]==2&v[1]==3&&v[2]==1)||(v[0]==3&v[1]==1&&v[2]==2)||(v[0]==3&&v[1]==2&&v[2]==1))){
     cout<<"Yes"<<endl;
     }else{
     cout<<"Np"<<endl;
     }
    }