#pragma GCC optimize("O3")

#include <iostream>
#include <cstring>
#include <string>
#include <cassert>
#include <random>
#include <cmath>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <queue>
#include <set>
using namespace std;

namespace fastinput {
	/** Interface */

	template <class T = int> inline T readInt();
	inline long double readDouble();
	inline int readUInt();
	inline int readChar();
	inline void readWord(char *s);
	inline bool readLine(char *s); // do not save '\n'
	inline bool isEof();
	inline int peekChar();
	inline bool seekEof();

	template <class T> inline void writeInt(T x, int len = -1);
	template <class T> inline void writeUInt(T x, int len = -1);
	inline void writeChar(int x);
	inline void writeWord(const char *s);
	inline void writeDouble(long double x, int len = 0);
	inline void flush();

	/** Read */

	static const int buf_size = 4096;

	static char buf[buf_size];
	static int buf_len = 0, buf_pos = 0;

	inline bool isEof() {
		if (buf_pos == buf_len) {
			buf_pos = 0, buf_len = fread(buf, 1, buf_size, stdin);
			if (buf_pos == buf_len)
				return 1;
		}
		return 0;
	}

	inline int getChar() {
		return isEof() ? -1 : buf[buf_pos++];
	}

	inline int peekChar() {
		return isEof() ? -1 : buf[buf_pos];
	}

	inline bool seekEof() {
		int c;
		while ((c = peekChar()) != -1 && c <= 32)
			buf_pos++;
		return c == -1;
	}

	inline int readChar() {
		int c = getChar();
		while (c != -1 && c <= 32)
			c = getChar();
		return c;
	}

	inline int readUInt() {
		int c = readChar(), x = 0;
		while ('0' <= c && c <= '9')
			x = x * 10 + c - '0', c = getChar();
		return x;
	}

	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;
	}

	inline long double readDouble() {
		int s = 1, c = readChar();
		long double x = 0;
		if (c == '-')
			s = -1, c = getChar();
		while ('0' <= c && c <= '9')
			x = x * 10 + c - '0', c = getChar();
		if (c == '.') {
			c = getChar();
			long double coef = 1;
			while ('0' <= c && c <= '9')
				x += (c - '0') * (coef *= 0.1), c = getChar();
		}
		return s == 1 ? x : -x;
	}

	inline void readWord(char *s) {
		int c = readChar();
		while (c > 32)
			*s++ = (char)c, c = getChar();
		*s = 0;
	}

	inline bool readLine(char *s) {
		int c = getChar();
		while (c != '\n' && c != -1)
			*s++ = (char)c, c = getChar();
		*s = 0;
		return c != -1;
	}

	/** Write */

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

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

	inline void flush() {
		if (write_buf_pos)
			fwrite(write_buf, 1, write_buf_pos, stdout), write_buf_pos = 0;
	}

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

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

	template <class T>
	inline void writeUInt(T x, int output_len) {
		char s[24];
		int n = 0;
		while (x || !n)
			s[n++] = (char)('0' + (char)(x % 10)), x /= 10;
		while (n < output_len)
			s[n++] = '0';
		while (n--)
			writeChar(s[n]);
	}

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

	inline void writeDouble(long double x, int output_len) {
		if (x < 0)
			writeChar('-'), x = -x;
		int t = (int)x;
		writeUInt(t), x -= t;
		writeChar('.');
		for (int i = output_len - 1; i > 0; i--) {
			x *= 10;
			t = std::min(9, (int)x);
			writeChar('0' + t), x -= t;
		}
		x *= 10;
		t = std::min(9, (int)(x + 0.5));
		writeChar('0' + t);
	}
}

using namespace fastinput;
using namespace std;

int h, w;
int c[5];
int arr[300];

int main() {
	//freopen("in.txt", "r", stdin);
	ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);

	cin >> h >> w;
	for (int y = 0; y < h; y++)
		for (int x = 0; x < w; x++) {
			static char c;
			cin >> c;
			arr[(int)c]++;
		}

	c[4] = (w / 2) * (h / 2);
	c[2] = (w / 2) * (h % 2) + (h / 2) * (w % 2);
	c[1] = (w % 2) * (h % 2);
	//cout << c[1] << " " << c[2] << " " << c[4] << endl;

	for (int i = 4; i >= 1; i--) {
		for (char l = 'a'; l <= 'z' && c[i] > 0; l++)
			while (arr[(int)l] >= i && c[i] > 0) {
				arr[(int)l] -= i;
				c[i]--;
				//cout << l << endl;
			}
		if (c[i] > 0) {
			cout << "No";
			return 0;
		}
	}

	cout << "Yes";

	return 0;
}

Measured memory_bytes: 256