/*~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=
*$* WRITER:kakitamasziru/OxOmisosiru *$*
~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=~=*/
#ifdef LOCAL_JUDGE
#define _GLIBCXX_DEBUG
#endif
#include <iostream> // cout, endl, cin
#include <string> // string, to_string, stoi
#include <vector> // vector
#include <algorithm> // min, max, swap, sort, reverse, lower_bound, upper_bound
#include <utility> // pair, make_pair
#include <tuple> // tuple, make_tuple
#include <cstdint> // int64_t, int*_t
#include <limits>//setprecision
#include <iomanip>
#include <map> // map
#include <queue> // queue, priority_queue
#include <set> // set,multiset
#include <stack> // stack
#include <deque> // deque
#include <math.h>//pow,,,
#include <cmath>//abs,,,
#include <bitset> // bitset
#include <numeric> //accumulate,,,
//#define endl "\n";
using namespace std;

const long long INF = 4000000000000000001;
const int inf = 1001001001;

void chmax(long long &a,long long b){if(a < b) a = b;}
void chmin(long long &a,long long b){if(a > b) a = b;}

//Solve N^M. This, mod_pow use Iterative Square Method.
long long mod_pow(long long N, long long M,long long MOD) {
    if (M == 0) return 1;
    long long res = mod_pow((N * N) % MOD, M / 2,MOD);
    //When end-of-a bit is 1, times simple N.
    if (M & 1) res = (res * N) % MOD;
    return res %= MOD;
}
long long gcd(long long a, long long b) {
    if (b == 0) return a; else return gcd(b, a % b);
}
long long lcm(long long a, long long b) {
    return a / gcd(a, b) * b ;
}



int main() {
    ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    
    int H,W;cin >> H >> W;
    vector<int> alpha(26);
    for(int i = 0;i<H;i++){
        for(int j = 0;j<W;j++){
            char C;cin >> C;
            alpha.at(C-'a')++;
        }
    }
    if(H % 2 == 1 && W % 2 == 1){
        int need4 = (H/2)*(W/2);
        int need2 = H/2+W/2;
        int odd = 1;
        for(int i = 0;i<26;i++){
            while(alpha.at(i) >= 4 && need4 > 0){
                alpha.at(i) -= 4;
                need4--;
            }
        }
        for(int i = 0;i<26;i++){
            while(alpha.at(i) >= 2 && need2 > 0){
                alpha.at(i) -= 2;
                need2--;
            }
        }
        for(int i = 0;i<26;i++){
            if(alpha.at(i) % 2 == 1 && odd > 0){
                alpha.at(i)--;
                odd--;
            }
        }
        if(need4 == 0 && need2 == 0 && odd == 0){
            cout << "Yes" << endl;
        }
        else{
            cout << "No" << endl;
        }
    }
    else if(H % 2 == 0 && W % 2 == 0){
        bool ok = true;
        for(int i = 0;i<26;i++){
            if(alpha.at(i) % 4 != 0) ok = false;
        }
        if(ok){
            cout << "Yes" << endl;
        }
        else{
            cout << "No" << endl;
        }
    }
    else{
        int need4 = (H/2)*(W/2);
        int need2 = (H*W-need4*4)/2;
        for(int i = 0;i<26;i++){
            while(alpha.at(i) >= 4 && need4 > 0){
                alpha.at(i) -= 4;
                need4--;
            }
        }
        for(int i = 0;i<26;i++){
            while(alpha.at(i) >= 2 && need2 > 0){
                alpha.at(i) -= 2;
                need2--;
            }
        }
        if(need4 == 0 && need2 == 0){
            cout << "Yes" << endl;
        }
        else{
            cout << "No" << endl;
        }
    }
}


Measured memory_bytes: 3644