#include <bits/stdc++.h>
using namespace std;
constexpr int N=337,L=1005,P=1e9+7;
constexpr int B=37;
int n,m,len[N],bp[L];
string s[N];
basic_string<int> ha[N],ah[N];
int* f[605][2][N],ans;
// 短的一端长度 i，左/右更短，长的从 s[j][k] 开始
inline void add(int &a,int b){
	if((a+=b)>=P) a-=P;
}
inline void makeha(const string &s,basic_string<int> &ha,basic_string<int> &ah){
	ha.resize(s.size()),ah.resize(s.size());
	for(unsigned i{0};i<s.size();++i){
		if(i>0) ha[i]=int((1ll*ha[i-1]*B+(s[i]-'a'))%P);
		else ha[i]=s[i]-'a';
	}
	for(int i{(int)s.size()-1};i>=0;--i){
		if(i+1<(int)s.size()) ah[i]=int((1ll*ah[i+1]*B+(s[i]-'a'))%P);
		else ah[i]=s[i]-'a';
	}
}
inline int getha(const basic_string<int> &ha,int l,int r){
	int v=ha[r];
	if(l>0) v=int((v-1ll*ha[l-1]*bp[r-l+1]%P+P)%P);
	return v;
}
inline int getrevha(const basic_string<int> &ah,int l,int r){
	int v=ah[l];
	if(r+1<(int)ah.size()) v=int((v-1ll*ah[r+1]*bp[r-l+1]%P+P)%P);
	return v;
}
int main(){
	cin.tie(0)->sync_with_stdio(0);
	cin>>n>>m;
	for(int i{1};i<=n;++i){
		string t; cin>>t;
		len[i]=(int)t.size();
		s[i]=t;
		makeha(s[i],ha[i],ah[i]);
	}
	for(int i{0};i<605;++i) for(int j:{0,1}) for(int k{1};k<=n;++k) f[i][j][k]=new int[len[k]+5]{};
	bp[0]=1; for(int i{1};i<605;++i) bp[i]=int(1ll*bp[i-1]*B%P);
	for(int i{1};i<=n;++i){
		if(len[i]>m) continue;
		int sz=len[i];
		if(!(m&1)){
			for(int j{0};j<sz;++j){
				int mn{min(j+1,sz-j-1)};
				if(getrevha(ah[i],j-mn+1,j)!=getha(ha[i],j+1,j+mn)) continue;
				if(j+1>sz-j-1) f[mn][1][i][j-mn]=1;
				else f[mn][0][i][j+mn+1]=1;
			}
		}
		else{
			for(int j{0};j<sz;++j){
				int mn{min(j,sz-j-1)};
				if(getrevha(ah[i],j-mn,j-1)!=getha(ha[i],j+1,j+mn)) continue;
				if(j>sz-j-1) f[mn][1][i][j-mn-1]=1;
				else f[mn][0][i][j+mn+1]=1;
			}
		}
	}
	for(int i{0};i<=m/2;++i){
		for(int j:{0,1}){
			for(int k{1};k<=n;++k){
				for(int l{0};l<=len[k];++l){
					if(!f[i][j][k][l]) continue;
					if(i==m/2){
						if(j==0&&l==len[k]) add(ans,f[i][j][k][l]);
						continue;
					}
					int rest{0};
					if(j==0) rest=len[k]-l;
					else rest=l+1;
					for(int t{1};t<=n;++t){
						if(i+len[t]>m/2) continue;
						if(j==0){
							if(rest<len[t]){
								if(getrevha(ah[t],len[t]-rest,len[t]-1)==getha(ha[k],l,len[k]-1))
									add(f[i+rest][!j][t][len[t]-rest-1],f[i][j][k][l]);
							}
							else{
								if(getrevha(ah[t],0,len[t]-1)==getha(ha[k],l,l+len[t]-1))
									add(f[i+len[t]][j][k][l+len[t]],f[i][j][k][l]);
							}
						}
						else{
							if(rest<=len[t]){
								if(getrevha(ah[t],0,rest-1)==getha(ha[k],0,l))
									add(f[i+rest][!j][t][rest],f[i][j][k][l]);
							}
							else{
								if(getrevha(ah[t],0,len[t]-1)==getha(ha[k],l-len[t]+1,l))
									add(f[i+len[t]][j][k][l-len[t]],f[i][j][k][l]);
							}
						}
					}
				}
			}
		}
	}
	cout<<ans<<'\n';
	return 0;
}