#include <iostream>
#include <algorithm>
#include <sstream>
#include <string>
#include <queue>
#include <cstdio>
#include <map>
#include <set>
#include <utility>
#include <stack>
#include <cstring>
#include <cmath>
#include <vector>
#include <ctime>
#include <bitset>
using namespace std;
#define pb push_back
#define sd(n) scanf("%d",&n)
#define sdd(n,m) scanf("%d%d",&n,&m)
#define sddd(n,m,k) scanf("%d%d%d",&n,&m,&k)
#define sld(n) scanf("%lld",&n)
#define sldd(n,m) scanf("%lld%lld",&n,&m)
#define slddd(n,m,k) scanf("%lld%lld%lld",&n,&m,&k)
#define sf(n) scanf("%lf",&n)
#define sff(n,m) scanf("%lf%lf",&n,&m)
#define sfff(n,m,k) scanf("%lf%lf%lf",&n,&m,&k)
#define ss(str) scanf("%s",str)
#define ans() printf("%d",ans)
#define ansn() printf("%d\n",ans)
#define anss() printf("%d ",ans)
#define lans() printf("%lld",ans)
#define lanss() printf("%lld ",ans)
#define lansn() printf("%lld\n",ans)
#define fansn() printf("%.10f\n",ans)
#define r0(i,n) for(int i=0;i<(n);++i)
#define r1(i,e) for(int i=1;i<=e;++i)
#define rn(i,e) for(int i=e;i>=1;--i)
#define rsz(i,v) for(int i=0;i<(int)v.size();++i)
#define szz(x) ((int)x.size())
#define mst(abc,bca) memset(abc,bca,sizeof abc)
#define lowbit(a) (a&(-a))
#define all(a) a.begin(),a.end()
#define pii pair<int,int>
#define pli pair<ll,int>
#define mp make_pair
#define lrt rt<<1
#define rrt rt<<1|1
#define X first
#define Y second
#define PI (acos(-1.0))
#define sqr(a) ((a)*(a))
typedef long long ll;
typedef unsigned long long ull;
const ll mod = 1000000000+7;
const double eps=1e-9;
const int inf=0x3f3f3f3f;
const ll infl = 10000000000000000;
const int maxn=  100+10;
const int maxm = 1000+10;
//Pretests passed
int in(int &ret)
{
    char c;
    int sgn ;
    if(c=getchar(),c==EOF)return -1;
    while(c!='-'&&(c<'0'||c>'9'))c=getchar();
    sgn = (c=='-')?-1:1;
    ret = (c=='-')?0:(c-'0');
    while(c=getchar(),c>='0'&&c<='9')ret = ret*10+(c-'0');
    ret *=sgn;
    return 1;
}

int cnt[30];
char s[maxn][maxn];
int main()
{
#ifdef LOCAL
    freopen("input.txt","r",stdin);
//    freopen("output.txt","w",stdout);
#endif // LOCAL
    int h,w;
    sdd(h,w);
    int row = h/2 + (h&1);
    int col = w/2 + (w&1);
    r1(i,h)ss(s[i]+1);
    r1(i,h)r1(j,w)
    {
        int idx = s[i][j]-'a';
        cnt[idx]++;
    }
    bool ok = 1;
    int one = 0, two = 0, four = 0;
    for(int i=1;i<=row;++i)
    {
        for(int j= 1;j<=col;++j)
        {
            int a = 4;
            if(i==row&&row==h/2+1)a/=2;
            if(j==col&&col==w/2+1)a/=2;
            if(a&1)++one;
            else if(a<=2)++two;
            else ++four;
        }
    }
    while(four--)
    {
        bool had = 0;
        for(int i=0;i<26;++i)
        {
            if(cnt[i]>=4)
            {
                had = 1;
                cnt[i]-=4;
                break;
            }
        }
        if(!had)
        {
            ok = 0;
            break;
        }
    }
    while(two--)
    {
        bool had = 0;
        for(int i=0;i<26;++i)
        {
            if(cnt[i]>=2)
            {
                had = 1;
                cnt[i]-=2;
                break;
            }
        }
        if(!had)
        {
            ok = 0;
            break;
        }
    }
    while(one--)
    {
        bool had = 0;
        for(int i=0;i<26;++i)
        {
            if(cnt[i])
            {
                had = 1;
                cnt[i]--;
                break;
            }
        }
        if(!had)
        {
            ok = 0;
            break;
        }
    }
    puts(ok?"Yes":"No");
    return 0;
}


Measured memory_bytes: 256