import std.algorithm;
import std.array;
import std.ascii;
import std.bigint;
import std.complex;
import std.container;
import std.conv;
import std.functional;
import std.math;
import std.range;
import std.stdio;
import std.string;
import std.typecons;

auto readInts() {
	return array(map!(to!int)(readln().strip().split()));
}
auto readInt() {
	return readInts()[0];
}
auto readLongs() {
	return array(map!(to!long)(readln().strip().split()));
}
auto readLong() {
	return readLongs()[0];
}

void readlnTo(T...)(ref T t) {
    auto s = readln().split();
    assert(s.length == t.length);
    foreach(ref ti; t) {
        ti = s[0].to!(typeof(ti));
        s = s[1..$];
    }
}

const real eps = 1e-10;

const long p = 1_000_000_000 + 7;

bool test(long h, long w, long[] c) {
    if(h % 2 == 0 && w % 2 == 0) {
        return c.all!(a => a % 4 == 0);
    }
    if(h % 2 == 1 && w % 2 == 1) {
        if(c.count!(a => a % 2 == 1) != 1) {
            return false;
        }
        foreach(i; iota(26)) {
            if(c[i] % 2 == 1) {
                c[i] -= 1;
            }
        }
        long l;
        foreach(i; iota(26)) {
            l += c[i] / 4;
        }
        return l * 4 >= (w-1) * (h-1);
    }
    if(c.any!(a => a % 2 == 1)) {
        return false;
    }
    long l;
    foreach(i; iota(26)) {
        l += c[i] / 4;
    }
    return l * 4 >= ((w/2)*2) * ((h/2)*2);
}

void main(){
    long h, w;
    readlnTo(h, w);
    long[] c = new long[](26);
    foreach(i; iota(h)) {
        auto l = readln().chomp();
        foreach(li; l) {
            c[li-'a']++;
        }
    }
    writeln(test(h, w, c) ? "Yes": "No");
}

