#include <cassert>
#include <cctype>
#include <cerrno>
#include <cfloat>
#include <ciso646>
#include <climits>
#include <clocale>
#include <cmath>
#include <csetjmp>
#include <csignal>
#include <cstdarg>
#include <cstddef>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <cwchar>
#include <cwctype>
#include <ccomplex>
#include <cfenv>
#include <cinttypes>
#include <cstdbool>
#include <cstdint>
#include <ctgmath>
#include <algorithm>
#include <bitset>
#include <complex>
#include <deque>
#include <exception>
#include <fstream>
#include <functional>
#include <iomanip>
#include <ios>
#include <iosfwd>
#include <iostream>
#include <istream>
#include <iterator>
#include <limits>
#include <list>
#include <locale>
#include <map>
#include <memory>
#include <new>
#include <numeric>
#include <ostream>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <stdexcept>
#include <streambuf>
#include <string>
#include <typeinfo>
#include <utility>
#include <valarray>
#include <vector>
#include <array>
#include <atomic>
#include <chrono>
#include <codecvt>
#include <condition_variable>
#include <forward_list>
#include <future>
#include <initializer_list>
#include <mutex>
#include <random>
#include <ratio>
#include <regex>
#include <scoped_allocator>
#include <system_error>
#include <thread>
#include <tuple>
#include <typeindex>
#include <type_traits>
#include <unordered_map>
#include <unordered_set>
#define rep(i, n) for(ll i = 0; i < (ll)(n); i++)
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
#define all(x) (x).begin(),(x).end()
#pragma GCC optimize("Ofast")
using namespace std;
typedef long long int ll;
typedef long double ld;
const ll INF=(1LL<<62);
const ld pi=acosl((ld)-1);
// const ll mod = 1000000007;
const ll mod = 1234567;
const int dx[4]={0,1,0,-1};
const int dy[4]={1,0,-1,0};
const int ddx[8]={1,0,-1,-1,-1,0,1,1};
const int ddy[8]={1,1,1,0,-1,-1,-1,0};
#define endn "\n"

bool solve(){
    ll h,w;cin>>h>>w;
    vector<vector<int>>s(h,vector<int>(w));
    vector<vector<int>>s2(h,vector<int>(w));
    rep(i,h)rep(j,w){
        s[i][j]=s2[i][j]=w*i+j;
    }

    rep(i,h)reverse(all(s2[i]));
    rep(i,h)rep(j,w){
        chmin(s[i][j],s2[i][j]);
    }   

    reverse(all(s2));
    rep(i,h)rep(j,w){
        chmin(s[i][j],s2[i][j]);
    }

    rep(i,h)reverse(all(s2[i]));
    rep(i,h)rep(j,w){
        chmin(s[i][j],s2[i][j]);
    }     

    map<int,int>mp;
    rep(i,h)rep(j,w){
        mp[s[i][j]]++;
    }

    // rep(i,h){
    //     rep(j,w)cout<<s[i][j];
    //     cout<<endl;
    // }

    
    ll max_1=0;
    ll max_2=0;
    for(auto&&i:mp){
        if(i.second%4==1)max_1++;
        if(i.second%4==2)max_2++;
    }

    vector<int>count(26,0);
    rep(i,h*w){
        char c;cin>>c;
        count[c-'a']++;
    }
    ll num1=0;
    ll num2=0;
    rep(i,26){
        ll num=count[i];
        if(num%4==0)continue;
        else if(num%4==1)num1++;
        else if(num%4==2)num2++;
        else if(num%4==3){
            num1++;
            num2++;
        }
    }
    // cout<<max_1<<" "<<max_2<<endl;
    // cout<<num1<<" "<<num2<<endl;
    cout<<(num1<=max_1 and num2<=max_2 ? "Yes" : "No")<<endl;
    return false;
}

signed main(){
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout<<fixed<<setprecision(30);
    solve();
}

Measured memory_bytes: 512