#include <bits/stdc++.h>   using namespace std;   const int MAXN = 23, MAXM = 2e4 + 10, LIM = (1 << MAXN), mod = 998244353;   int n, f[1 << MAXN], g[1 << MAXN], F[1 << MAXN];   long long ans;   int pcnt[1 << MAXN], psum[1 << MAXN], tag[1 << MAXN];   char s[MAXN][MAXM];   int cnt[MAXN][26];   int main() {     for (int i = (0); i <= (22); i++) tag[1 << i] = i;     for (int i = (1); i <= ((1 << 23) - 1); i++) {       pcnt[i] = pcnt[i - (i & -i)] + 1;       psum[i] = psum[i - (i & -i)] + tag[(i & -i)] + 1;     }     scanf( %d , &n);     for (int i = (0); i <= (n - 1); i++) {       scanf( %s , s[i] + 1);       int len = strlen(s[i] + 1);       for (int j = (1); j <= (len); j++) {         cnt[i][s[i][j] -  a ]++;       }     }     for (int i = (1); i <= ((1 << n) - 1); i++) f[i] = 1;     for (int i = (0); i <= (25); i++) {       g[0] = 1e9;       for (int j = (1); j <= ((1 << n) - 1); j++) {         g[j] = min(g[j ^ (j & -j)], cnt[tag[(j & -j)]][i]);         f[j] = 1LL * f[j] * (g[j] + 1) % mod;       }     }     for (int i = (1); i <= ((1 << n) - 1); i++) {       if ((pcnt[i] & 1))         F[i] = f[i];       else         F[i] = mod - f[i];     }     for (int i = (0); i <= (22); i++) {       for (int j = (1); j <= ((1 << n) - 1); j++) {         if (j >> i & 1) {           F[j] = (F[j] + F[j ^ (1 << i)]) % mod;         }       }     }     for (int j = (1); j <= ((1 << n) - 1); j++) {       ans ^= (1LL * F[j] * pcnt[j] * psum[j]);     }     printf( %lld , ans);     return 0;   }   