#include <bits/stdc++.h>

//#pragma GCC optimize("ffast-math")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,tune=native")

using namespace std;

/** Interface */

inline int readChar();
template <class T = int> inline T readInt();
template <class T> inline void writeInt( T x, char end = 0 );
inline void writeChar( int x );
inline void writeWord( const char *s );

/** Read */

static const int buf_size = 4096;

inline int getChar() {
    static char buf[buf_size];
    static int len = 0, pos = 0;
    if (pos == len)
        pos = 0, len = fread(buf, 1, buf_size, stdin);
    if (pos == len)
        return -1;
    return buf[pos++];
}

inline int readChar() {
    int c = getChar();
    while (c <= 32)
        c = getChar();
    return c;
}

template <class T>
inline T readInt() {
    int s = 1, c = readChar();
    T x = 0;
    if (c == '-')
        s = -1, c = getChar();
    while ('0' <= c && c <= '9')
        x = x * 10 + c - '0', c = getChar();
    return s == 1 ? x : -x;
}

/** Write */

static int write_pos = 0;
static char write_buf[buf_size];

inline void writeChar( int x ) {
    if (write_pos == buf_size)
        fwrite(write_buf, 1, buf_size, stdout), write_pos = 0;
    write_buf[write_pos++] = x;
}

template <class T>
inline void writeInt( T x, char end ) {
    if (x < 0)
        writeChar('-'), x = -x;

    char s[24];
    int n = 0;
    while (x || !n)
        s[n++] = '0' + x % 10, x /= 10;
    while (n--)
        writeChar(s[n]);
    if (end)
        writeChar(end);
}

inline void writeWord( const char *s ) {
    while (*s)
        writeChar(*s++);
}

struct Flusher {
    ~Flusher() {
        if (write_pos)
            fwrite(write_buf, 1, write_pos, stdout), write_pos = 0;
    }
} flusher;

typedef long long ll;
typedef long double ld;

int main() {
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    int h, w;
    cin >> h >> w;
    vector<int> cnt(26);
    for (int i = 0; i < h; ++i) {
        for (int j = 0; j < w; ++j) {
            char ch;
            cin >> ch;
            ++cnt[ch - 'a'];
        }
    }
    sort(cnt.begin(), cnt.end());
    for (int i = 0; i < (h + 1) / 2; ++i) {
        for (int j = 0; j < (w + 1) / 2; ++j) {
            set<pair<int, int>> kek;
            kek.insert(make_pair(i, j));
            kek.insert(make_pair(h - i - 1, j));
            kek.insert(make_pair(i, w - j - 1));
            kek.insert(make_pair(h - i - 1, w - j - 1));
            if (kek.size() == 4) {
                bool f = true;
                for (int k = 0; k < 26; ++k) {
                    if (cnt[k] >= 4) {
                        cnt[k] -= 4;
                        f = false;
                        break;
                    }
                }
                if (f) {
                    cout << "No";
                    return 0;
                }
                continue;
            }
            if (kek.size() == 2) {
                bool f = true;
                for (int k = 0; k < 26; ++k) {
                    if (cnt[k] >= 2) {
                        cnt[k] -= 2;
                        f = false;
                        break;
                    }
                }
                if (f) {
                    cout << "No";
                    return 0;
                }
                continue;
            }
        }
    }
    cout << "Yes";
    return 0;
}

Measured memory_bytes: 256