Language: C++

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using Edge = pair<int, int>;
using Graph = vector<vector<Edge>>;
#define REP(i, n) for (int i = 0; i < (n); ++i)
#define SORT(v) sort((v).begin(), (v).end())
#define RSORT(v) sort((v).rbegin(), (v).rend())
const ll MOD = 1000000007;
const ll nmax = 8;
const ll INF = 1e9;
bool graph[nmax][nmax];
vector<vector<ll>> dist = vector<vector<ll>>(nmax, vector<ll>(nmax, INF));
void warshall_floyd(ll n)
{
    for (size_t i = 0; i < n; i++)
    {
        for (size_t j = 0; j < n; j++)
        {
            for (size_t k = 0; k < n; k++)
            {
                dist[j][k] = min(dist[j][k], dist[j][i] + dist[i][k]);
            }
        }
    }
}

class UnionFind
{
public:
    vector<ll> Parent;

    UnionFind(ll N)
    {
        Parent = vector<ll>(N, -1);
    }
    ll find(ll A)
    {
        if (Parent[A] < 0)
            return A;
        return Parent[A] = find(Parent[A]);
    }

    ll size(ll A)
    {
        return -Parent[find(A)];
    }

    bool Union(ll A, ll B)
    {
        A = find(A);
        B = find(B);
        if (A == B)
        {
            return false;
        }
        if (size(A) < size(B))
            swap(A, B);

        Parent[A] += Parent[B];
        Parent[B] = A;

        return true;
    }
};

ll gcd(ll a, ll b)
{
    if (b == 0)
        return a;
    return gcd(b, a % b);
}

ll lcm(ll a, ll b)
{
    ll g = gcd(a, b);
    return a / g * b;
}

ll mulMod(ll a, ll b)
{
    return (((a % MOD) * (b % MOD)) % MOD);
}

ll powMod(ll a, ll p)
{
    if (p == 0)
    {
        return 1;
    }
    else if (p % 2 == 0)
    {
        ll half = powMod(a, p / 2);
        return mulMod(half, half);
    }
    else
    {
        return mulMod(powMod(a, p - 1), a);
    }
}

ll ceil(ll a, ll b)
{
    return (a + b - 1) / b;
}

const string YES = "Yes";
const string NO = "No";

int main()
{
    ll H, W;
    cin >> H >> W;
    map<char, int> cnt;
    for (int i = 0; i < H; i++)
    {
        string str;
        cin >> str;
        for (int j = 0; j < W; j++)
        {
            cnt[str[j]]++;
        }
    }

    if (H % 2 == 0 && W % 2 == 0)
    {
        for (auto &&i : cnt)
        {
            if (i.second % 4 != 0)
            {
                cout << "No" << endl;
                return 0;
            }
        }
        cout << "Yes" << endl;
        return 0;
    }
    else if (H % 2 == 0 && W % 2 != 0)
    {
        if (W == 1)
        {
            for (auto &&i : cnt)
            {
                if (i.second % 2 != 0)
                {
                    cout << "No" << endl;
                    return 0;
                }
            }
            cout << "Yes" << endl;
            return 0;
        }
        else
        {
            int cnt4 = 0, cnt2 = 0;
            for (auto &&i : cnt)
            {
                cnt4 += i.second / 4;
                i.second %= 4;
                cnt2 += i.second / 2;
                i.second %= 2;

                if (i.second != 0)
                {
                    cout << "No" << endl;
                    return 0;
                }
            }
            if (cnt4 == H / 2 && cnt2 == H / 2)
            {
                cout << "Yes" << endl;
                return 0;
                else
                {
                    cout << "No" << endl;
                    return 0;
                }
            }
        }
        else if (H % 2 != 0 && W % 2 == 0)
        {
            swap(H, W);
            if (W == 1)
            {
                for (auto &&i : cnt)
                {
                    if (i.second % 2 != 0)
                    {
                        cout << "No" << endl;
                        return 0;
                    }
                }
                cout << "Yes" << endl;
            }
            else
            {
                int cnt4 = 0, cnt2 = 0;
                for (auto &&i : cnt)
                {
                    cnt4 += i.second / 4;
                    i.second %= 4;
                    cnt2 += i.second / 2;
                    i.second %= 2;

                    if (i.second != 0)
                    {
                        cout << "No" << endl;
                        return 0;
                    }
                }
                if (cnt4 == H / 2 && cnt2 == H / 2)
                {
                    cout << "Yes" << endl;
                    return 0;
                }
                else
                {
                    cout << "No" << endl;
                    return 0;
                }
            }
        }
        else
        {
            if (W < H)
            {
                swap(H, W);
            }

            if (H == 1 && W == 1)
            {
                cout << "Yes" << endl;
                return 0;
            }
            if (H == 1)
            {
                int cnt2 = 0, cnt1 = 0;
                for (auto &&i : cnt)
                {
                    cnt2 += i.second / 2;
                    i.second %= 2;

                    if (i.second != 0)
                    {
                        cnt1++;
                    }
                }
                if (cnt1 == 1 && cnt2 == W / 2)
                {
                    cout << "Yes" << endl;
                    return 0;
                }
                else
                {
                    cout << "No" << endl;
                    return 0;
                }
            }
            else
            {
                int cnt4 = 0, cnt2 = 0, cnt1 = 0;
                for (auto &&i : cnt)
                {
                    cnt4 += i.second / 4;
                    i.second %= 4;
                    cnt2 += i.second / 2;
                    i.second %= 2;

                    if (i.second != 0)
                    {
                        cnt1++;
                    }
                }
                if (cnt1 == 1 && cnt2 == H / 2 + W / 2 && cnt4 == (H / 2) * (W / 2))
                {
                    cout << "Yes" << endl;
                    return 0;
                }
                else
                {
                    cout << "No" << endl;
                    return 0;
                }
            }
        }
        return 0;
    }

Compiler output:
a.cc: In function 'int main()':
a.cc:173:17: error: expected '}' before 'else'
  173 |                 else
      |                 ^~~~
a.cc:170:13: note: to match this '{'
  170 |             {
      |             ^