#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
typedef pair<ll,ll> P;
typedef pair<int,int> Pi;
#define rep(i,n) for(ll i=0;i<n;i++)
#define FOR(i,a,b) for(ll i=a;i<b;i++)
#define fi first
#define se second
#define endl "\n"

template<typename T> inline bool chmax(T &a, T b){if(a<b){a=b;return true;}return false;}
template<typename T> inline bool chmin(T &a, T b){if(a>b){a=b;return true;}return false;}
template<typename T> ostream& operator<<(ostream& s,const complex<T>& d) {return s<<"("<<d.real()<<", "<<d.imag()<< ")";}
template<typename T1, typename T2> ostream& operator<<(ostream& s,const pair<T1,T2>& d) {return s<<"("<<d.first<<", "<<d.second<<")";}
template<typename T> ostream& operator<<(ostream& s, const vector<T>& d){int len=d.size();rep(i,len){s<<d[i];if(i<len-1) s<<" ";}return s;}
template<typename T> ostream& operator<<(ostream& s,const vector<vector<T>>& d){int len=d.size();rep(i,len){s<<d[i]<<endl;}return s;}
template<typename T> ostream& operator<<(ostream& s,const set<T>& v){s<<"{ ";for(auto itr=v.begin();itr!=v.end();++itr) {if (itr!=v.begin()) {s<< ", ";}s<<(*itr);}s<<" }";return s;}
template<typename T> ostream& operator<<(ostream& s,const multiset<T>& v){s<<"{ ";for(auto itr=v.begin();itr!=v.end();++itr) {if (itr!=v.begin()) {s<< ", ";}s<<(*itr);}s<<" }";return s;}
template<typename T1, typename T2> ostream& operator<<(ostream& s,const map<T1,T2>& m){s<<"{"<<endl;for(auto itr=m.begin();itr!=m.end();++itr){s<<" "<<(*itr).first<<" : "<<(*itr).second<<endl;}s<<"}"<<endl;return s;}

const ll mod=1'000'000'007;
const ll inf=1'000'000'000'000'000'00;
const int INF=1'000'000'000;
const double EPS=1e-10;
const double PI=acos(-1);

int main(){
    cin.tie(0);ios::sync_with_stdio(false);
    int h,w;
    cin>>h>>w;
    vector<string> s(h);
    map<char,int> mp;
    rep(i,h){
        cin>>s[i];
        rep(j,w){
            mp[s[i][j]]++;
        }
    }
    vector<vector<char>> ans(h,vector<char>(w,'#'));
    rep(i,h)rep(j,w){
        if(ans[i][j]!='#') continue;
        if(i!=h-1-i && j!=w-1-j){
            for(auto &[x,y]:mp){
                if(y>=4){
                    ans[i][j]=ans[i][w-1-j]=ans[h-1-i][j]=ans[h-1-i][w-1-j]=x;
                    y-=4;
                    break;
                }
            }
        }
    }
    rep(i,h)rep(j,w){
        if(ans[i][j]!='#') continue;
        if(i==h-1-i && j!=w-1-j){
            for(auto &[x,y]:mp){
                if(y>=2){
                    ans[i][j]=ans[i][w-1-j]=x;
                    y-=2;
                    break;
                }
            }
        }
        if(i!=h-1-i && j==w-1-j){
            for(auto &[x,y]:mp){
                if(y>=2){
                    ans[i][j]=ans[h-1-i][j]=x;
                    y-=2;
                    break;
                }
            }
        }
    }
    rep(i,h)rep(j,w){
        if(ans[i][j]!='#') continue;
        if(i==h-1-i && j==w-1-j){
            for(auto &[x,y]:mp){
                if(y>=1){
                    ans[i][j]=x;
                    y-=1;
                    break;
                }
            }
        }
    }
    rep(i,h)rep(j,w){
        if(ans[i][j]=='#'){
            cout<<"No"<<endl;
            return 0;
        }
    }
    cout<<"Yes"<<endl;
}

Measured memory_bytes: 3668