#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <vector>
#include <list>
#include <set>
#include <map>
#include <queue>
#include <stack>
#include <cctype>
#include <climits>
#include <string>
#include <bitset>
#include <cfloat>
#include <unordered_set>
using namespace std;
typedef long double ld;
typedef long long int ll;
typedef unsigned long long int ull;
typedef vector<int> vi;
typedef vector<char> vc;
typedef vector<bool> vb;
typedef vector<double> vd;
typedef vector<string> vs;
typedef vector<ll> vll;
typedef vector<pair<int,int> > vpii;
typedef vector<vector<int> > vvi;
typedef vector<vector<char> > vvc;
typedef vector<vector<string> > vvs;
typedef vector<vector<ll> > vvll;
#define rep(i,n) for(int i = 0; i < (n); ++i)
#define rrep(i,n) for(int i = 1; i <= (n); ++i)
#define drep(i,n) for(int i = (n) - 1; i >= 0; --i)
#define fin(ans) cout<<(ans)<<endl
#define STI(s) atoi(s.c_str())
#define mp(p,q) make_pair(p, q)
#define pb(n) push_back(n)
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define Sort(a) sort(a.begin(), a.end())
#define Rort(a) sort(a.rbegin(), a.rend())
#define MATHPI acos(-1)
template <class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
template <class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
struct io{io(){ios::sync_with_stdio(false);cin.tie(0);};};
const int MOD = 1000000007;
const int INF = INT_MAX;
const ll LLINF = 1LL<<62;



int main(void) {

    int h,w;
    cin>>h>>w;
    int alpha[26]={0};
    rep(i,h)rep(j,w){
        char c;
        cin>>c;
        alpha[c-'a']++;
    }
    bool ch=true;
    if(h==1&&w==1){
        fin("Yes");
        return 0;
    } else if(h==1||w==1){
        int odd=0;
        for(int i=0;i<26;i++){
            if(alpha[i]%2==1)odd++;
        }
        if(max(h,w)%2==0&&odd==0){
            ch=true;
        } else if(max(h,w)%2==1&&odd==1){
            ch=true;
        } else {
            ch=false;
        }
    }else if(h%2==0&&w%2==0){
        for(int i=0;i<26;i++){
            if(alpha[i]%4!=0)ch=false;
        }
    } else if((h%2==1||w%2==1)&&(h%2==0||w%2==0)){
        int four=0;
        int odd=0;
        int needfour=(h/2)*(w/2);
        for(int i=0;i<26;i++){
            if(alpha[i]%2==1){
                odd++;
                alpha[i]--;
            }
            if(alpha[i]>=4){
                four+=alpha[i]/4;
            }
        }
        if(odd!=0)ch=false;
        if(needfour>four)ch=false;
        // for(int i=0;i<26;i++){
        //     cout<<char('a'+i)<<" "<<alpha[i]<<endl;
        // }
        // cout<<h/2<<" "<<w/2<<endl;
        // cout<<needfour<<" "<<four<<" "<<odd<<endl;
    } else {
        int needfour=((h-1)/2)*((w-1)/2);
        int odd=0;
        int four=0;
        for(int i=0;i<26;i++){
            if(alpha[i]%2==1){
                odd++;
                alpha[i]--;
            }
            if(alpha[i]>=4){
                four+=alpha[i]/4;
            }

        }
        // cout<<needfour<<" "<<four<<" "<<odd<<endl;
        if(needfour>four)ch=false;
        if(odd!=1)ch=false;
        
    }
    if(ch)fin("Yes");
    else fin("No");
}



Measured memory_bytes: 384