func_code_string: #include <bits/stdc++.h>   using namespace std;   template <typename T>   void dbg(T t) {     cerr << t << endl;   }   template <typename T, typename... Args>   void dbg(T t, Args... args) {     cerr << t <<    ;     dbg(args...);   }   int main() {     ios::sync_with_stdio(0);     cin.tie(0);     int n, a, spec = 3;     int t[2] = {1, 2};     cin >> n;     for (int i = 0; i < n; i++) {       cin >> a;       if (spec == a) {         cout <<  NO  << endl;         return 0;       }       for (int j = 0; j < 2; j++)         if (t[j] != a) swap(t[j], spec);     }     cout <<  YES  << endl;     return 0;   }   