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

int main()
{
    int h, w;
    cin>>h>>w;
    vector<int> cnt(128);
    for(int i=0; i<h; ++i) {
        string s;
        cin>>s;
        for(char c: s) ++cnt[c];
    }
    int n4=0, n2=0, n1=0;
    for(int c: cnt) {
        n4+=c/4;
        c%=4;
        n2+=c/2;
        c%=2;
        n1+=c;
    }
    if (n1>1) return cout<<"No"<<endl, 0;
    if (n1 and h*w%2==0) return cout<<"No"<<endl, 0;
    if (n2 and h%2==0 and w%2==0) return cout<<"No"<<endl, 0;

    if (h%2==0 and w%2) swap(h, w);
    if (h%2 and w%2) {
        cout<<(n2>(h-1)/2+(w-1)/2 ? "No" : "Yes")<<endl;
        return 0;
    }
    if (h%2) {
        cout<<(n2>w/2 ? "No" : "Yes")<<endl;
        return 0;
    }
    cout<<"Yes"<<endl;
}
