#include <cctype>
#include <cfloat>
#include <climits>
#include <cmath>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>

#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <ios>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <utility>
#include <valarray>
#include <vector>

#if __cplusplus >= 201103L
#include <array>
#include <forward_list>
#include <random>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <unordered_map>
#include <unordered_set>
#endif

#define F first
#define S second
#define MP make_pair
#define pb push_back
#define all(a) a.begin(), a.end()
#define lcm( a, b ) (a)/__gcd((a),(b))*(b)
#define endl '\n'

using namespace std;

typedef long long LL;
typedef pair< int, int > P;
typedef pair< LL, LL > LP;
typedef pair< int, P > iP;
typedef pair< P, P > PP;

static const int INF = INT_MAX;
static const LL LINF = LLONG_MAX;
static const int MIN = INT_MIN;
static const LL LMIN = LLONG_MIN;
static const int MOD = 1000000007;
static const int SIZE = 500005;

const int dx[] = {0, -1, 1, 0};
const int dy[] = {-1, 0, 0, 1};

vector< int > Div( int n ) {
    vector< int > ret;
    for( int i = 1; i * i <= n; ++i ) {
        if( n % i == 0 ) {
            ret.pb( i );

            if( i * i != n ) ret.pb( n / i );
        }
    }
    sort( all( ret ) );
    return ret;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    int h, w;
    cin >> h >> w;
    int al_cnt[26] = {};
    for( int i = 0; i < h; ++i ) {
        string s;
        cin >> s;
        for( int j = 0; j < w; ++j ) {
            ++al_cnt[s[j] - 'a'];

        }
    }

    if( h % 2 == 1 && w % 2 == 1 ) {
        int pos = 0;
        while( pos < 26 && al_cnt[pos] % 2 == 0 ) ++pos;
        
        if( pos == 26 ) {
            cout << "No" << endl;
            return 0;

        }
        --al_cnt[pos];

    }

    int g;
    if( h % 2 == 1 && w % 2 == 1 ) {
        g = (h / 2) + (w / 2);

    } else if( h % 2 == 1 ) {
        g = w / 2;

    } else if( w % 2 == 1 ) {
        g = h / 2;

    } else {
        g = 0;

    }

    for( int i = 0; i < 26 && g > 0; ++i ) {
        if( al_cnt[i] % 4 == 2 ) {
            --g;
            al_cnt[i] -= 2;

        }
    }

    if( g != 0 ) {
        int pos = 0;
        while( g > 0 && pos < 26 ) {
            while( g > 0 && al_cnt[pos] > 0 ) {
                --g;
                al_cnt[pos] -= 2;

            }
            ++pos;

        }
    }

    g = (h / 2) * (w / 2);
    for( int i = 0; i < 26 && g > 0; ++i ) {
        if( al_cnt[i] % 4 == 0 ) {
            g -= al_cnt[i] / 4;
            al_cnt[i] = 0;

        }
    }

    if( g != 0 ) {
        cout << "No" << endl;
        return 0;

    }

    for( int i = 0; i < 26; ++i ) {
        if( al_cnt[i] != 0 ) {
            cout << "No" << endl;
            return 0;

        }
    }
    cout << "Yes" << endl;

    return 0;
}


Measured memory_bytes: 256