func_code_string: #include <bits/stdc++.h>   using namespace std;   void in(int &x) {     register int c = getchar();     x = 0;     for (; (c < 48 || c > 57); c = getchar())       ;     for (; c > 47 && c < 58; c = getchar()) {       x = (x << 1) + (x << 3) + c - 48;     }   }   const int N = 1 << 24;   long long dp[N];   string s[10004];   int main() {     int n, i, j, mask, full = N - 1;     in(n);     for (i = 0; i < n; i++) {       cin >> s[i];       mask = 0;       for (j = 0; j < 3; j++) mask |= 1 << (s[i][j] -  a );       mask ^= full;       dp[mask]++;     }     for (i = 0; i < 24; i++) {       for (mask = N - 1; mask >= 0; mask--)         if (mask & (1 << i)) {           dp[mask ^ (1 << i)] += dp[mask];         }     }     long long ret = 0;     for (i = 0; i < N; i++) ret ^= 1ll * (n - dp[i]) * (n - dp[i]);     printf( %lld n , ret);     return 0;   }   