func_code_string: #include <bits/stdc++.h>   using namespace std;   int i, j, k, n, m, an;   int f[(1 << 24)], g[(1 << 24)], h[(1 << 24)];   char p[3];   int main() {     scanf( %d , &n);     for (i = 1; i <= n; i++) {       scanf( %s , p);       int s = 0;       for (j = 0; j <= 2; j++) s |= 1 << (p[j] -  a );       g[s]++;     }     m = (1 << 24) - 1;     for (i = 1; i <= m; i++) {       int A = i & -i, B = i ^ A;       if (!B) {         f[i] = g[i];         continue;       }       int C = B & -B, D = B ^ C;       if (!D) {         f[i] = f[B] + f[D | A] - f[D] + g[A | C];         continue;       }       int E = D & -D, F = D ^ E;       f[i] = f[F] - f[F | E] - f[F | C] - f[F | A] + f[i ^ A] + f[i ^ C] +              f[i ^ E] + g[A | C | E];     }     for (i = 1; i <= m; i++) {       int A = i & -i, B = i ^ A, C = m ^ B, D = m ^ i;       h[i] = h[B] + f[C] - f[D];       an ^= h[i] * h[i];     }     printf( %d n , an);     return 0;   }   