#include<iostream>

#include<stdio.h>

#include<string.h>

#include<math.h>

#include<algorithm>

#include<vector>

#include<set>

#include<map>

#include<string>

#include<queue>

#include<stack>

#include <iomanip>

using namespace std;

#define LL long long

const int INF=0x3f3f3f3f;

const int N=45;

LL ans[20005][2];

int aa,ab,ba,bb;

int F(int i,int j,int l,int r)

{

    int x=r;

    x+=(l*bb);

    x+=(j*ba*bb);

    x+=(i*ab*ba*bb);

    return x;

}

int main()

{

    //freopen("data.in","r",stdin);

    int n,k;

    while(cin>>n>>k)

    {

        ab=0;aa=0;ba=0;bb=0;

        string stmp;

        int locomotive;

        cin>>stmp;

        if(stmp=="AA") locomotive=0;

        if(stmp=="AB") locomotive=1;

        if(stmp=="BA") locomotive=2;

        if(stmp=="BB") locomotive=3;

        for(int i=1;i<=n;++i)

        {

            cin>>stmp;

            if(stmp=="AA") ++aa;

            if(stmp=="AB") ++ab;

            if(stmp=="BA") ++ba;

            if(stmp=="BB") ++bb;

        }

        ++aa;++ab;++ba;++bb;

        memset(ans,0,sizeof(ans));

        if(locomotive==0||locomotive==2)

        ans[0][0]=1;

        else

        ans[0][1]=1;

        LL sum=0;

        for(int i=0;i<aa;++i)

        for(int j=0;j<ab;++j)

        for(int l=0;l<ba;++l)

        for(int r=0;r<bb;++r)

        if(i+j+l+r<=k)

        {

            int x=F(i,j,l,r);

            if(i+j+l+r==k)

            {

                if(locomotive==0||locomotive==1)

                sum+=ans[x][0];

                else

                sum+=ans[x][1];

            }

            if(ans[x][0]!=0)

            {

                if(i+1<aa)

                ans[F(i+1,j,l,r)][0]+=ans[x][0];

                if(j+1<ab)

                ans[F(i,j+1,l,r)][1]+=ans[x][0];

            }

            if(ans[x][1]!=0)

            {

                if(l+1<ba)

                ans[F(i,j,l+1,r)][0]+=ans[x][1];

                if(r+1<bb)

                ans[F(i,j,l,r+1)][1]+=ans[x][1];

            }

        }

        if(sum==0)

        cout<<"NO"<<endl;

        else

        {cout<<"YES"<<endl;cout<<sum<<endl;}

    }

    return 0;

}