func_code_string: #include <bits/stdc++.h>   using namespace std;   void show() {}   template <typename T, typename... V>   void show(T t, V... v) {     cerr << t;     if (sizeof...(v)) cerr <<  ,  ;     show(v...);   }   template <class X>   bool mini(X& a, const X& b) {     if (a > b) {       a = b;       return true;     }     return false;   }   template <class X>   bool maxi(X& a, const X& b) {     if (a < b) {       a = b;       return true;     }     return false;   }   typedef const int& ci;   int n;   int dp[1 << 24];   void enter() {     cin >> n;     for (int i = 1, _b = (n) + 1; i < _b; ++i) {       char a, b, c;       cin >> a >> b >> c;       ++dp[(1 << a -  a ) | (1 << b -  a ) | (1 << c -  a )];     }   }   void solve() {     int MASK = (1 << 24);     for (int i = 0; i < 24; ++i)       for (int mask = 0; mask < MASK; ++mask)         if (mask >> i & 1) dp[mask] += dp[mask ^ (1 << i)];     int res = 0;     for (int mask = 0; mask < MASK; ++mask)       if (dp[mask] != n) res ^= (n - dp[mask]) * (n - dp[mask]);     cout << res;   }   int main() {     ios_base ::sync_with_stdio(false);     cin.tie(nullptr);     enter();     solve();     cerr <<   nTime elapsed:   << 1000 * clock() / CLOCKS_PER_SEC <<  ms ;   }   