#include <bits/stdc++.h>
using namespace std;

int main() {
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int h, w; cin >> h >> w;
    int a = (h & 1) * (w & 1);
    int b = (h & 1) * w + (w & 1) * h - a * 2;
    int c = h * w - (b + a);
    b /= 2, c /= 4;
    string s;
    map<char, int> m;
    for (int i = 0; i < h; i++) {
        string s; cin >> s;
        for (auto &x: s) m[x]++;
    }
    for (auto &iter: m) {
        while (iter.second >= 4 && c) c--, iter.second -= 4;
        while (iter.second >= 2 && b) b--, iter.second -= 2;
        while (iter.second >= 1 && a) a--, iter.second -= 1;
    }
    if (a | b | c) cout << "No\n";
    else cout << "Yes\n";
    return 0;
}