Language: C++

signed main()
{
    std::ios::sync_with_stdio(false);
    std::cin.tie(0);
 
    int2(a, b);
    vector<string> yui(a);
    rep(i, a) {
        cin >> yui[i];
    }
 
    vi cnt(26, 0);
    rep(i, a) {
        rep(j, b) {
            cnt[yui[i][j] - 'a']++;
        }
    }
 
    vi kyoko(4, 0);
    rep(i, cnt.size()) {
        kyoko[cnt[i]%4]++;
    }
 
    if (a % 2 && b % 2) {
        if (kyoko[3]) {
            kyoko[3]--;
            kyoko[1]++;
            kyoko[2]++;
        }
        if (kyoko[3]) {
            cout << "No" << endl;
            return 0;
        }
        if (kyoko[1] == 1 && 
                kyoko[2] <= (a/2+b/2)) {
            cout << "Yes" << endl;
            return 0;
        } else {
            cout << "No" << endl;
            return 0;
        }
    } else if (a % 2) {
        if (kyoko[3] || kyoko[1]) {
            cout << "No" << endl;
            return 0;
        }
        if (kyoko[2] <= b / 2) {
            cout << "Yes" << endl;
        } else {
            cout << "No" << endl;
        }
        return 0;
    } else if (b % 2) {
        if (kyoko[3] || kyoko[1]) {
            cout << "No" << endl;
            return 0;
        }
        if (kyoko[2] <= a / 2) {
            cout << "Yes" << endl;
        } else {
            cout << "No" << endl;
        }
        return 0;
    } else {
        if (kyoko[1] || kyoko[2] || kyoko[3]) {
            cout << "No" << endl;
        } else {
            cout << "Yes" << endl;
        }
    }
    return 0;
 
}

Compiler output:
a.cc: In function 'int main()':
a.cc:3:10: error: 'std::ios' has not been declared
    3 |     std::ios::sync_with_stdio(false);
      |          ^~~
a.cc:4:10: error: 'cin' is not a member of 'std'
    4 |     std::cin.tie(0);
      |          ^~~
a.cc:1:1: note: 'std::cin' is defined in header '<iostream>'; this is probably fixable by adding '#include <iostream>'
  +++ |+#include <iostream>
    1 | signed main()
a.cc:6:10: error: 'a' was not declared in this scope
    6 |     int2(a, b);
      |          ^
a.cc:6:13: error: 'b' was not declared in this scope
    6 |     int2(a, b);
      |             ^
a.cc:6:5: error: 'int2' was not declared in this scope; did you mean 'int'?
    6 |     int2(a, b);
      |     ^~~~
      |     int
a.cc:7:5: error: 'vector' was not declared in this scope
    7 |     vector<string> yui(a);
      |     ^~~~~~
a.cc:7:12: error: 'string' was not declared in this scope
    7 |     vector<string> yui(a);
      |            ^~~~~~
a.cc:7:20: error: 'yui' was not declared in this scope
    7 |     vector<string> yui(a);
      |                    ^~~
a.cc:8:9: error: 'i' was not declared in this scope
    8 |     rep(i, a) {
      |         ^
a.cc:8:5: error: 'rep' was not declared in this scope
    8 |     rep(i, a) {
      |     ^~~
a.cc:12:5: error: 'vi' was not declared in this scope; did you mean 'void'?
   12 |     vi cnt(26, 0);
      |     ^~
      |     void
a.cc:19:7: error: expected ';' before 'kyoko'
   19 |     vi kyoko(4, 0);
      |       ^~~~~~
      |       ;
a.cc:20:12: error: 'cnt' was not declared in this scope; did you mean 'int'?
   20 |     rep(i, cnt.size()) {
      |            ^~~
      |            int
a.cc:25:13: error: 'kyoko' was not declared in this scope
   25 |         if (kyoko[3]) {
      |             ^~~~~
a.cc:30:13: error: 'kyoko' was not declared in this scope
   30 |         if (kyoko[3]) {
      |             ^~~~~
a.cc:31:13: error: 'cout' was not declared in this scope
   31 |             cout << "No" << endl;
      |             ^~~~
a.cc:31:29: error: 'endl' was not declared in this scope
   31 |             cout << "No" << endl;
      |                             ^~~~
a.cc:34:13: error: 'kyoko' was not declared in this scope
   34 |         if (kyoko[1] == 1 &&
      |             ^~~~~
a.cc:36:13: error: 'cout' was not declared in this scope
   36 |             cout << "Yes" << endl;
      |             ^~~~
a.cc:36:30: error: 'endl' was not declared in this scope
   36 |             cout << "Yes" << endl;
      |                              ^~~~
a.cc:39:13: error: 'cout' was not declared in this scope
   39 |             cout << "No" << endl;
      |             ^~~~
a.cc:39:29: error: 'endl' was not declared in this scope
   39 |             cout << "No" << endl;
      |                             ^~~~
a.cc:43:13: error: 'kyoko' was not declared in this scope
   43 |         if (kyoko[3] || kyoko[1]) {
      |             ^~~~~
a.cc:44:13: error: 'cout' was not declared in this scope
   44 |             cout << "No" << endl;
      |             ^~~~
a.cc:44:29: error: 'endl' was not declared in this scope
   44 |             cout << "No" << endl;
      |                             ^~~~
a.cc:47:13: error: 'kyoko' was not declared in this scope
   47 |         if (kyoko[2] <= b / 2) {
      |             ^~~~~
a.cc:48:13: error: 'cout' was not declared in this scope
   48 |             cout << "Yes" << endl;
      |             ^~~~
a.cc:48:30: error: 'endl' was not declared in this scope
   48 |             cout << "Yes" << endl;
      |                              ^~~~
a.cc:50:13: error: 'cout' was not declared in this scope
   50 |             cout << "No" << endl;
      |             ^~~~
a.cc:50:29: error: 'endl' was not declared in this scope
   50 |             cout << "No" << endl;
      |                             ^~~~
a.cc:54:13: error: 'kyoko' was not declared in this scope
   54 |         if (kyoko[3] || kyoko[1]) {
      |             ^~~~~
a.cc:55:13: error: 'cout' was not declared in this scope
   55 |             cout << "No" << endl;
      |             ^~~~
a.cc:55:29: error: 'endl' was not declared in this scope
   55 |             cout << "No" << endl;
      |                             ^~~~
a.cc:58:13: error: 'kyoko' was not declared in this scope
   58 |         if (kyoko[2] <= a / 2) {
      |             ^~~~~
a.cc:59:13: error: 'cout' was not declared in this scope
   59 |             cout << "Yes" << endl;
      |             ^~~~
a.cc:59:30: error: 'endl' was not declared in this scope
   59 |             cout << "Yes" << endl;
      |                              ^~~~
a.cc:61:13: error: 'cout' was not declared in this scope
   61 |             cout << "No" << endl;
      |             ^~~~
a.cc:61:29: error: 'endl' was not declared in this scope
   61 |             cout << "No" << endl;
      |                             ^~~~
a.cc:65:13: error: 'kyoko' was not declared in this scope
   65 |         if (kyoko[1] || kyoko[2] || kyoko[3]) {
      |             ^~~~~
a.cc:66:13: error: 'cout' was not declared in this scope
   66 |             cout << "No" << endl;
      |             ^~~~
a.cc:66:29: error: 'endl' was not declared in this scope
   66 |             cout << "No" << endl;
      |                             ^~~~
a.cc:68:13: error: 'cout' was not declared in this scope
   68 |             cout << "Yes" << endl;
      |             ^~~~
a.cc:68:30: error: 'endl' was not declared in this scope
   68 |             cout << "Yes" << endl;
      |                              ^~~~