#include <bits/stdc++.h>
using namespace std;
#define int long long
using ll=long long;
using vi=vector<int>;
using pii=pair<int,int>;
#define ALL(c) begin(c),end(c)
#define RALL(c) rbegin(c),rend(c)
#define ITR(i,b,e) for(auto i=(b);i!=(e);++i)
#define FORE(x,c) for(auto &x:c)
#define REPF(i,a,n) for(int i=a,i##len=(int)(n);i<i##len;++i)
#define REP(i,n) REPF(i,0,n)
#define REPR(i,n) for(int i=(int)(n);i>=0;--i)
#define SZ(c) ((int)c.size())
#define CONTAIN(c,x) (c.find(x)!=end(c))
#define OUTOFRANGE(y,x,h,w) (y<0||x<0||y>=h||x>=w)
#define dump(...)
const int DX[9]={0,1,0,-1,1,1,-1,-1,0},DY[9]={-1,0,1,0,-1,1,1,-1,0};
#define INF (1001001001)
#define INFLL (1001001001001001001ll)
template<class T> ostream& operator << (ostream &os,const vector<T> &v) {
    ITR(i,begin(v),end(v)) os<<*i<<(i==end(v)-1?"":" "); return os; }
template<class T> istream& operator >> (istream &is,vector<T> &v) {
    ITR(i,begin(v),end(v)) is>>*i; return is; }
template<class T> istream& operator >> (istream &is, pair<T,T> &p) {
    is>>p.first>>p.second; return is; }
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;}
template <class T> using heap = priority_queue<T,vector<T>,greater<T>>;
//------------------------------------------------------------------------------
struct before_main_function {
    before_main_function() {
        #ifdef int
            #undef INF
            #define INF INFLL
            #define stoi stoll
        #endif
        cin.tie(0);ios::sync_with_stdio(false);
        cout<<setprecision(15)<<fixed;
        #define endl "\n"
    }
} before_main_function;
//------------------8<------------------------------------8<--------------------

signed main() {
    int H,W;
    cin>>H>>W;
    vector<string> a(H);
    cin>>a;
    map<char,int> cnt;
    REP(i,H) {
        REP(j,W) {
            cnt[a[i][j]]++;
        }
    }

    int f=(W/2)*(H/2);
    REPF(i,'a','z'+1) {
        if(f>=cnt[i]/4) {
            f-=cnt[i]/4;
            cnt[i]%=4;
        } else {
            cnt[i]-=f;
            f=0;
            break;
        }
    }
    if(f>0) {
        cout<<"No"<<endl;
        return 0;
    }

    if(H%2 && W%2) {
        int t=(W-1)/2+(H-1)/2;
        REPF(i,'a','z'+1) {
            if(t>=cnt[i]/2) {
                t-=cnt[i]/2;
                cnt[i]%=2;
            } else {
                cnt[i]-=t;
                t=0;
                break;
            }
        }
        if(t>0) {
            cout<<"No"<<endl;
            return 0;
        } else {
            cout<<"Yes"<<endl;
            return 0;
        }
    }
    else if(H%2 || W%2) {
        int t=0;
        if(H%2==1) t=W/2;
        else t=H/2;
        REPF(i,'a','z'+1) {
            if(t>=cnt[i]/2) {
                t-=cnt[i]/2;
                cnt[i]%=2;
            } else {
                cnt[i]-=t;
                t=0;
                break;
            }
        }
        if(t>0) {
            cout<<"No"<<endl;
            return 0;
        } else {
            cout<<"Yes"<<endl;
            return 0;
        }
    } else {
        cout<<"Yes"<<endl;
        return 0;
    }
    return 0;
}


Measured memory_bytes: 256