import java.io.*
import java.util.*
import java.lang.*
import java.lang.Math.*


fun solve() {
    val (H, W) = rd.readListInt()
    val A = (0 until H).map { rd.readString() }

    val mp = mutableMapOf<Char, Int>()
    A.forEach{ it.forEach{ mp[it] = (mp[it] ?: 0) + 1 }}

    if (H==1 && W==1) {
        println("Yes")
        return
    } else if (W==1) {
        if (H%2==0) {
            for (pr in mp) {
                if (pr.value%2==1) {
                    println("No")
                    return
                }
            }
            println("Yes")
            return
        } else {
            var odd = 0
            for (pr in mp) {
                if (pr.value%2==1) {
                    odd++
                }
            }
            val ans = if (odd==1) "Yes" else "No"
            println(ans)
            return
        }
    } else if (H==1) {
        if (W%2==0) {
            for (pr in mp) {
                if (pr.value%2==1) {
                    println("No")
                    return
                }
            }
            println("Yes")
            return
        } else {
            var odd = 0
            for (pr in mp) {
                if (pr.value%2==1) {
                    odd++
                }
            }
            val ans = if (odd==1) "Yes" else "No"
            println(ans)
            return
        }
    }

    val mp1 = mutableMapOf<Int, Int>()
    var ch = 0
    for (i in 0 until (H+1)/2) {
        if (H%2==1 && i == (H+1)/2-1) {
            for (j in 0 until (W+1)/2) {
                if (W%2==1 && j == (W+1)/2-1) mp1[ch++] = 1
                else mp1[ch++] = 2
            }
        } else {
            for (j in 0 until (W+1)/2) {
                if (W%2==1 && j == (W+1)/2-1) mp1[ch++] = 2
                else mp1[ch++] = 4
            }
        }
    }

    errPrintln(mp.values.sum())
    errPrintln(mp1.values.sum())

    val B = mp1.values.sortedDescending()

    for (v1 in B) {
        var ok = false
        for ((k, v) in mp) {
            if (v >= v1) {
                mp[k] = mp[k]!! - v1
                //mp1.remove(pr1.key)
                ok = true
                break
            }
        }
        if (!ok) {
            println("No")
            return
        }
    }

    println("Yes")
}


//val rd = debug.Reader("etc", "code-festival-2017-quala", "c", "sample-1")
val rd = Reader()


fun main(args: Array<String>) {
    try {
        var exception: Throwable? = null
        val sth = Thread(null, SolveThread(), "solveThread", 128 * 1024 * 1024)
        sth.setUncaughtExceptionHandler { _, e -> exception = e }
        sth.start(); sth.join()
        if (exception != null) throw exception!! }
    catch (e: Exception) { throw e }
    finally { rd.close() }
}
const val MOD = 1_000_000_007L; const val INF = Int.MAX_VALUE/2; const val LINF = Long.MAX_VALUE/2
const val EPS = 1e-9; fun DBLEQ(a: Double, b: Double): Boolean {return abs(a - b) < EPS}
data class IntPair(val first: Int, val second: Int)
data class To(val idx: Int, val cost: Long)
typealias ALI = ArrayList<Int>
fun <T>edge(V: Int): Array<ArrayList<T>> { return Array(V){ArrayList<T>()} }
val errPrintln: (Any) -> Unit = { msg -> System.err.println(msg) }
fun rAssert(exp: Boolean, lazyMsg: () -> String = {""}) {
    if (!exp) { val msg = lazyMsg(); errPrintln("EAssert Error: $msg"); throw Error(msg) }
}
fun tAssert(exp: Boolean, lazyMsg: () -> String = {""}) {
    if (!exp) { val msg = lazyMsg(); errPrintln("TAssert Error: $msg"); Thread.sleep(3000) }
}
class SolveThread : Runnable {
    override fun run() { solve() }
}
class Reader {
    private val br = BufferedReader(InputStreamReader(System.`in`))
    val readString: () -> String = { br.readLine() }
    val readInt: () -> Int = { br.readLine().toInt() }
    val readLong: () -> Long = { br.readLine().toLong() }
    val readIntArray: () -> IntArray = { br.readLine().split(' ').map { it.toInt() }.toIntArray() }
    val readLongArray: () -> LongArray = { br.readLine().split(' ').map { it.toLong() }.toLongArray() }
    val readListInt: () -> List<Int> = { br.readLine().split(' ').map { it.toInt() } }
    val readListLong: () -> List<Long> = { br.readLine().split(' ').map { it.toLong() } }
    val readListIntCol: (Int) -> List<Int> = { N -> (0 until N).map { readInt() } }
    val readListIntCols: (Int) -> List<List<Int>> = { N -> (0 until N).map { br.readLine().split(' ').map { it.toInt() } } }
    val readListLongCol: (Int) -> List<Long> = { N -> (0 until N).map { readLong() } }
    val readListLongCols: (Int) -> List<List<Long>> = { N -> (0 until N).map { br.readLine().split(' ').map { it.toLong() } } }
    val close: () -> Unit = { br.close() }
    protected fun finalize() { close() }
}


Measured memory_bytes: 41928