#include<iostream>

int main() {
  int N;
  char cAA,cAB,cBA,cBB;
  std::cin>>N>>cAA>>cAB>>cBA>>cBB;
  if (cAA=='A'&&cAB=='A') {
    std::cout<<'1'<<std::endl;
  } else if (cAB=='B'&&cBB=='B') {
    std::cout<<'1'<<std::endl;
  } else if (N==2) {
  std::cout<<'1'<<std::endl;
  } else if (
    (cAA=='A'&&cAB=='B'&&cBA=='A'&&cBB=='A')||
    (cAA=='B'&&cAB=='B'&&cBA=='A'&&cBB=='A')||
    (cAA=='B'&&cAB=='A'&&cBA=='B'&&cBB=='A')||
    (cAA=='B'&&cAB=='A'&&cBA=='B'&&cBB=='B')
  ) {
    long long ans = 1;
    for (int i = 0; i < N-3; i++) {
      ans*=2;
      ans%=1000000007;
    }
    std::cout<<ans<<std::endl;
  } else {
    long long f[1000];
    f[0] = 1;
    f[1] = 1;
    for (int i = 2; i <= 999; i++) {
      f[i] = f[i-1] + f[i-2];
      f[i] %=1000000007;
    }
    std::cout<<f[N-2]<<std::endl;
  }
  return 0;
}

#define _USE_MATH_DEFINES
#include <bits/stdc++.h>
using namespace std;

//template
#define rep(i,a,b) for(int i=(int)(a);i<(int)(b);i++)
#define ALL(v) (v).begin(),(v).end()
using ll=long long int;
const int inf = 0x3fffffff; const ll INF = 0x1fffffffffffffff; const double eps=1e-12;
template<typename T>inline bool chmax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
template<typename T>inline bool chmin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
//end

template<unsigned mod=998244353>struct fp {
   using uint=unsigned; uint v;
   static uint get_mod(){return mod;}
   int inv() const{
      int tmp,a=v,b=mod,x=1,y=0;
      while(b)tmp=a/b,a-=tmp*b,swap(a,b),x-=tmp*y,swap(x,y);
      if(x<0){x+=mod;} return x;
   }
   fp(ll x=0){init(x%mod+mod);}
   fp& init(uint x){v=(x<mod?x:x-mod); return *this;}
   fp operator-()const{return fp()-*this;}
   fp pow(ll t){fp res=1,b=*this; while(t){if(t&1)res*=b;b*=b;t>>=1;} return res;}
   fp& operator+=(const fp& x){return init(v+x.v);}
   fp& operator-=(const fp& x){return init(v+mod-x.v);}
   fp& operator*=(const fp& x){v=ll(v)*x.v%mod; return *this;}
   fp& operator/=(const fp& x){v=ll(v)*x.inv()%mod; return *this;}
   fp operator+(const fp& x)const{return fp(*this)+=x;}
   fp operator-(const fp& x)const{return fp(*this)-=x;}
   fp operator*(const fp& x)const{return fp(*this)*=x;}
   fp operator/(const fp& x)const{return fp(*this)/=x;}
   bool operator==(const fp& x)const{return v==x.v;}
   bool operator!=(const fp& x)const{return v!=x.v;}
   friend istream& operator>>(istream& is,fp& x){is>>x.v; return is;}
   friend ostream& operator<<(ostream& os,const fp& x){os<<x.v; return os;}
}; using Fp=fp<>;
template<typename T>struct factorial {
   vector<T> Fact,Finv,Inv;
   factorial(int maxx){
      Fact.resize(maxx); Finv.resize(maxx); Inv.resize(maxx);
      Fact[0]=Fact[1]=Finv[0]=Finv[1]=Inv[1]=1;
      rep(i,2,maxx){Fact[i]=Fact[i-1]*i;} Finv[maxx-1]=Fact[maxx-1].inv();
      for(int i=maxx-1;i>=2;i--){Finv[i-1]=Finv[i]*i; Inv[i]=Finv[i]*Fact[i-1];}
   }
   T fact(int n,bool inv=0){if(n<0)return 0; return (inv?Finv[n]:Fact[n]);}
   T inv(int n){if(n<0)return 0; return Inv[n];}
   T nPr(int n,int r,bool inv=0){if(n<0||n<r||r<0)return 0; return fact(n,inv)*fact(n-r,inv^1);}
   T nCr(int n,int r,bool inv=0){if(n<0||n<r||r<0)return 0; return fact(n,inv)*fact(r,inv^1)*fact(n-r,inv^1);}
};

Fp memo[3010][3010];
bitset<3010> used[3010];
Fp rec(int n,int k){
   if(n<k)return 0;
   if(used[n][k])return memo[n][k];
   used[n][k]=1;
   if(k==0){
      return memo[n][k]=(n==0);
   }
   return memo[n][k]=rec(n-1,k-1)+rec(n,k*2);
}

int main(){
   int n,k;
   cin>>n>>k;
   cout<<rec(n,k)<<'\n';
   return 0;
}