func_code_string: #include <bits/stdc++.h>   using namespace std;   unordered_map<long long int, long long int> mp;   long long int n, m, k, ans;   long long int a[22][22];   int dx[] = {1, -1, 0, 0};   int dy[] = {0, 0, 1, -1};   void dfs1(int ex, int ey, int sx, int sy, long long int cur) {     if (sx == ex and sy == ey) mp[cur]++;     if (sx < ex) dfs1(ex, ey, sx + 1, sy, cur ^ (a[sx][sy]));     if (sy < ey) dfs1(ex, ey, sx, sy + 1, cur ^ (a[sx][sy]));   }   void dfs(int x, int y, long long int cur) {     if (x == n - 1 and y == m - 1) cur ^= a[x][y], ans += mp[cur ^ k];     if (x < n - 1) dfs(x + 1, y, cur ^ (a[x][y]));     if (y < m - 1) dfs(x, y + 1, cur ^ (a[x][y]));   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     cin >> n >> m >> k;     for (int i = 0; i < n; i++)       for (int j = 0; j < m; j++) cin >> a[i][j];     int mid = (n + m - 2) / 2;     for (int i = 0; i < n; i++) {       for (int j = 0; j < m; j++) {         if (i + j == mid) {           dfs1(i, j, 0, 0, 0);           dfs(i, j, 0);           mp.clear();         }       }     }     cout << ans <<   n ;     return 0;   }   