Language: C++

#include <iostream>
#include <string>
#include <vector>
#include <utility>
#include <algorithm>
#include <functional>
#include <map>

using namespace std;
using ll = long long;
using pll = pair<ll,ll>;

#define reps(i,s,n) for(int (i) = (s) ;(i) < (n); (i)++)
#define rep(i,n) reps(i,0,n)

int main(){
    int h,w;
    cin >> h >> w;
    map<char,int> mp;
    string str;
    rep(i,h){
        cin >> str;
        rep(j,str.length()){
            mp[ str[j] ]++;
        }
    }
bool f = false;
    if(h == 1 || w == 1){
        for(auto elem:mp){
            if(elem.second % 2 == 1){
                if(!f)
                    f=true;
                else{
                    cout<< "No" << endl;
                    return 0;
                }
            }
            cout << elem.first << "," << elem.second << endl;
        }
        cout << "Yes" << endl;
        return 0;
    }else{
        if(h%2 == 0 && w % 2 == 0){
            for(auto elem:mp){
                    if(elem.second % 4 != 0){
                        cout<< "No" << endl;
                        return 0;
                    }
                }
            }
            cout << "Yes" << endl;
        }else if((h % 2 == 1 && w % 2 == 0)){
            int cnt = 0;
            for(auto elem:mp){
                    if(elem.second % 2 == 1){
                        cout << "No" << endl;
                        return 0;
                    }
                    if(elem.second % 4 == 2){
                        cnt++;
                        if(cnt > w/2){
                            cout << "No"<<endl;
                            return 0;
                        }
                    }
                }
            }
            cout << "Yes" << endl;

        }else if((h % 2 == 0 && w % 2 == 1)){
            int cnt = 0;
            for(auto elem:mp){
                    if(elem.second % 2 == 1){
                        cout << "No" << endl;
                        return 0;
                    }
                    if(elem.second % 4 == 2){
                        cnt++;
                        if(cnt > h/2){
                            cout << "No"<<endl;
                            return 0;
                        }
                    }
                }
            }
            cout << "Yes" << endl;
        }else if((h % 2 == 1 && w % 2 == 1)){
            int cnt = 0,odd = 0;
            for(auto elem:mp){
                    if(elem.second % 2 == 1){
                        odd++;
                        if(odd > 1){
                            cout << "No" << endl;
                            return 0;
                        }
                    }
                    if(elem.second % 4 == 2){
                        cnt++;
                        if(cnt > (h+w)/2){
                            cout << "No"<<endl;
                            return 0;
                        }
                    }
                }
            }
            if(odd == 1){
            cout << "Yes" << endl;
            }else{cout << "No" <<endl;}
        }

    }



    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:52:10: error: 'else' without a previous 'if'
   52 |         }else if((h % 2 == 1 && w % 2 == 0)){
      |          ^~~~
a.cc: At global scope:
a.cc:70:10: error: expected unqualified-id before 'else'
   70 |         }else if((h % 2 == 0 && w % 2 == 1)){
      |          ^~~~
a.cc:86:13: error: 'cout' does not name a type
   86 |             cout << "Yes" << endl;
      |             ^~~~
a.cc:87:9: error: expected declaration before '}' token
   87 |         }else if((h % 2 == 1 && w % 2 == 1)){
      |         ^
a.cc:87:10: error: expected unqualified-id before 'else'
   87 |         }else if((h % 2 == 1 && w % 2 == 1)){
      |          ^~~~
a.cc:106:13: error: expected unqualified-id before 'if'
  106 |             if(odd == 1){
      |             ^~
a.cc:108:14: error: expected unqualified-id before 'else'
  108 |             }else{cout << "No" <<endl;}
      |              ^~~~
a.cc:109:9: error: expected declaration before '}' token
  109 |         }
      |         ^
a.cc:111:5: error: expected declaration before '}' token
  111 |     }
      |     ^
a.cc:115:5: error: expected unqualified-id before 'return'
  115 |     return 0;
      |     ^~~~~~
a.cc:116:1: error: expected declaration before '}' token
  116 | }
      | ^