#include <iostream>
#include <algorithm>
#include <utility>
#include <string>
#include <vector>
#include <set>
#include <stack>
#include <queue>
#include <map>
#include <math.h>
#include <string.h>
#include <iomanip>
#include <numeric>
#include <cstdlib>
#include <cstdint>
#include <cmath>
#include <functional>
#include <limits>
#include <cassert>

using namespace std;

using ll = long long;
using pll = pair<ll, ll>;
using vl = vector<ll>;
using vll = vector<vl>;
using vpll = vector<pll>;

void debug_out() { std::cout << endl; }
 
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cout << H << " ";
  debug_out(T...);
}

#ifdef LOCAL
#define debug(...) cout << "debug: "; debug_out(__VA_ARGS__)
#else
#define debug(...) 
#endif

#define rep(i, n) for (int i = 0; i < (int)(n); i++)
#define rrep(i, n) for (int i = ((int)(n)-1); i >= 0; i--)
#define Rep(i, n) for (long long i = 0; i< (long long)(n); i++)
#define RRep(i,n) for (long long i = ((long long)(n)-1); i>=0; i--)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()

struct Edge{
    int to;
    int weight;
    Edge(int t, int w) : to(t), weight(w){ }
};

struct edge{
    int from;
    int to;
    int weight;
    edge(int f,int t,int w) : from(f), to(t), weight(w){ }
};


using Graph = vector<vector<Edge>>;
using graph = vector<vector<int>>;
using edges = vector<edge>;

template <class T>
inline bool chmin(T &a, T b){
    if (a > b){
        a = b;
        return true;
    }
    return false;
}

template <class T>
inline bool chmax(T &a, T b){
    if (a < b){
        a = b;
        return true;
    }
    return false;
}

template <class T>
T lcm(T a, T b){
    return (a*b)/gcd(a,b);
}

bool isPalindrome(string s){
    string t = s;
    reverse(all(t));
    return s==t;
}

constexpr ll INF = 1e9+7;

vector<int> dx = {-1,0,1,0};
vector<int> dy = {0,-1,0,1};

template<class T>
T binary(T key,const vector<T> &g){
    T ng = -1;
    T ok = (T)g.size();
    while(abs(ok-ng)>1){
        T mid = (ok+ng)/2;
        if(gcd(g[mid],key)==1){
            ok = mid;
        }
        else{
            ng = mid;
        }
    }
    return ok;
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    int h,w; cin >> h >> w;
    vector<string> s(h);
    rep(i,h) cin >> s[i];
    vector<int> a(26,0);
    rep(i,h){
        rep(j,w){
            a[s[i][j]-'a']++;
        }
    }
    if(h==1 || w==1){
        int flag = 0;
        rep(i,26){
            if(a[i]%2==1) flag++;
        }
        if(flag<=1) cout << "Yes" << endl;
        else cout << "No" << endl;
        return 0;
    }

    if(h%2==1 && w%2==1){
        int two = 0;
        int one = 0;
        rep(i,26){
            if(a[i]%4==2){
                two++;
            }
            else if(a[i]%2==1){
                one++;
            }
        }
        int d = w/2 + h/2;
        if(two<=d && one==1){
            cout << "Yes" << endl;
        }
        else{
            cout << "No" << endl;
        }
        return 0;
    }
    else if(h%2==0 && w%2==0){
        rep(i,26){
            if(a[i]%4){
                cout << "No" << endl;
                return 0;
            }
        }
        cout << "Yes" << endl;
    }
    else{
        int flag = 0;
        rep(i,26){
            if(a[i]%4==0) continue;
            else if(a[i]%4==2) flag++;
            else{
                cout << "No" << endl;
                return 0;
            }
        }
        int d;
        if(h%2==0) d = h/2;
        else d = w/2;
        if(flag <= d){
            cout << "Yes" << endl;
        }
        else cout << "No"<< endl;
    }
}

Measured memory_bytes: 256