#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<iomanip>
#include<math.h>
#include<complex>
#include<queue>
#include<deque>
#include<stack>
#include<map>
#include<set>
#include<bitset>
#include<functional>
#include<assert.h>
#include<numeric>
using namespace std;
#define REP(i,m,n) for(int i=(int)(m) ; i < (int) (n) ; ++i )
#define rep(i,n) REP(i,0,n)
using ll = long long;
const int inf=1e9+7;
const ll longinf=1LL<<60 ;
const ll mod=1e9+7 ;

template<typename T>
struct SegmentTree{
private:
    int n;
    T E;
    vector<T> node;
    inline void updatef(T& x,T& y){
        x = y;
        //x += y;
        //x = max(x,y);
        //x = min(x,y);
    }
    inline T queryf(T& x,T& y){
        //return x*y;
        return (x+y)%mod;
        //return max(x,y);
        //return min(x,y);
    }

public:
    SegmentTree(int sz,T E_):E(E_){
        n=1;
        while(n<sz)n<<=1;
        node.resize(2*n-1,E);
    }

    SegmentTree(vector<T>& A,T E_):E(E_){
        int sz=A.size();
        n=1;
        while(n<sz)n<<=1;
        node.resize(2*n-1,E);
        rep(i,sz)node[i+n-1]=A[i];
        for(int i=n-2;i>=0;--i){
            node[i]=queryf(node[2*i+1], node[2*i+2]);
        }
    }
    void update(int k,T x){
        k+=n-1;
        updatef(node[k],x);
        while(k>0){
            k=(k-1)/2;
            node[k]=queryf(node[2*k+1], node[2*k+2]);
        }
    }
       //[a,b)での和を返す
    T get(int a,int b,int k=0,int l=0,int r=-1){
        if(r<0)r=n;
        if(r<=a||b<=l)return E;
        if(a<=l&&r<=b)return node[k];
        T xl=get(a,b,2*k+1,l,(l+r)/2);
        T xr=get(a,b,2*k+2,(l+r)/2,r);
        return queryf(xl, xr);
    }
};

vector<ll> inv,fact,invfact;
void mod_build(int n=101010){
    fact.resize(n+1);
    inv.resize(n+1);
    invfact.resize(n+1);
    fact[0]=inv[0]=invfact[0]=1;
    inv[1]=1;
    rep(i,n){
        fact[i+1]=fact[i]*(i+1)%mod;
        if(i>0)inv[i+1]=mod-inv[mod%(i+1)]*(mod/(i+1))%mod;
        invfact[i+1]=invfact[i]*inv[i+1]%mod;
    }
}
ll perm(int n,int k){
    if(n<0||k<0||k>n)return 0;
    return fact[n]*invfact[n-k]%mod;
}
ll comb(int n,int k){
    if(n<0||k<0||k>n)return 0;
    return (fact[n]*invfact[n-k]%mod)*invfact[k]%mod;
}
ll powmod(ll n,ll k){
    k%=mod-1;
    if(k<0)k+=mod-1;
    ll ret=1;
    while(k){
        if(k&1)ret=ret*n%mod;
        n=n*n%mod;
        k>>=1;
    }
    return ret;
}
int main(){
    int n,m;
    cin>>n>>m;
    string s;
    cin>>s;
    int len=0;
    while(len<m&&s[len]==s[0])++len;
    if(len==m){
        vector<ll> ans(n+1);
        ans[0]=2,ans[1]=1;
        rep(i,n-1)ans[i+2]=(ans[i+1]+ans[i])%mod;
        cout<<ans[n]<<endl;
        return 0;
    }
    if(n%2){
        cout<<0<<endl;
        return 0;
    }
    if (len%2==0)++len;
    int cnt=0;
    rep(i,m){
        if(s[i]!=s[0]){
            if(cnt%2)len=min(len,cnt);
            cnt=0;
        }
        else ++cnt;
    }
    n/=2;
    len = (len+1)/2;
    SegmentTree<ll> sg(n+5,0);
    sg.update(0,1);
    rep(i,n+1){
        ll ret=sg.get(max(0,i+1-len),i+1);
        sg.update(i+1,ret);
    }
    ll ans=0;
    rep(i,min(n,len)){
        ans+=sg.get(max(0,n-len),n-i);
    }
    cout<<2*ans%mod<<endl;

    return 0;
}


Measured memory_bytes: 2692