fun main(args: Array<String>) {
  val (h, w) = readLine()!!.split(" ").map { it.toInt() }
  val board = Array(h, { readLine()!! })
  val oneCount = if (h % 2 == 1 && w % 2 == 1) 1 else 0
  val twoCount = (if (h % 2 == 1) w / 2 else 0) + (if (w % 2 == 1) h / 2 else 0)
  val fourCount = h / 2 * w / 2

  val charCounts = IntArray(26)
  for (row in board) {
    for (c in row) {
      charCounts[c - 'a']++
    }
  }

  val oddCount = charCounts.filter { it % 2 == 1 }.size
  if (oddCount > oneCount) {
    println("No")
    return
  }

  val oddIndex = charCounts.indexOfFirst { it % 2 == 1 }
  if (oddIndex >= 0) {
    charCounts[oddIndex]--
  }

  val twoModFourCount = charCounts.filter { it % 4 == 2 }.size
  if (twoModFourCount > twoCount) {
    println("No")
    return
  }

  println("Yes")
}
