// MagicDark
#include <bits/stdc++.h>
#define debug cerr << "[" << __LINE__ << "] "
#define SZ(x) (int) x.size() - 1
#define all(x) x.begin(), x.end()
#define ms(x, y) memset(x, y, sizeof x)
#define F(i, x, y) for (int i = (x); i <= (y); i++)
#define DF(i, x, y) for (int i = (x); i >= (y); i--)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
template <typename T> inline void chkmax(T& x, T y) {x = max(x, y);}
template <typename T> inline void chkmin(T& x, T y) {x = min(x, y);}
template <typename T> inline void read(T &x) {
	x = 0; int f = 1; char c = getchar();
	for (; !isdigit(c); c = getchar()) if (c == '-') f = -f;
	for (; isdigit(c); c = getchar()) x = (x << 1) + (x << 3) + (c ^ 48);
	x *= f;
}
mt19937_64 mrand(chrono::steady_clock::now().time_since_epoch().count());
const int N = 350, T = 610, MOD = 1e9 + 7;
inline void add(int &x, ll y) {x = (x + y) % MOD;}
const ull base = 328478951;
int n, l, tot, a[T], b[T], f[510][T][2], len[N], id[N][T], ans;
string s[N];
vector <ull> t[N], rt[N];
ull w[26], pw[N];
ull qq(int x, int l, int r) {
	if (l > r) return 0;
	// debug << l << ' ' << r << ' ' << x << " " << t[x].size() << '\n';
	return t[x][r] - t[x][l - 1] * pw[r - l + 1];
}
ull rqq(int x, int l, int r) {
	if (l > r) return 0;
	return rt[x][l] - rt[x][r + 1] * pw[r - l + 1];
}
signed main() {
	cin.tie(0) -> sync_with_stdio(0); // don't use puts
	cin >> n >> l;
	pw[0] = 1;
	F(i, 1, n) pw[i] = pw[i - 1] * base;
	F(i, 0, 25) w[i] = mrand();
	F(i, 1, n) {
		cin >> s[i];
		// if ((len[i] = s[i].size()) == 1) dot++;
		len[i] = s[i].size();
		// debug << "! " << i << " " << len[i] << endl;
		t[i].resize(len[i] + 1);
		rt[i].resize(len[i] + 2);
		F(j, 1, len[i]) {
			tot++;
			t[i][j] = t[i][j - 1] * base + w[s[i][j - 1] - 'a'];
			id[i][j] = tot;
			a[tot] = i;
			b[tot] = j;
		}
		DF(j, len[i], 1) rt[i][j] = rt[i][j + 1] * base + w[s[i][j - 1] - 'a'];
		// tot += s[i].size();
	}
	f[0][0][0] = 1;
	F(i, 0, l / 2)
		F(j, 0, tot) {
			// debug << f[i][j][0] << ' ' << f[i][j][1] << '\n';
			if (i * 2 + b[j] == l) {
				if (qq(a[j], len[a[j]] - b[j] + 1, len[a[j]]) == rqq(a[j], len[a[j]] - b[j] + 1, len[a[j]])) {
					// debug << "!\n";
					add(ans, f[i][j][0]);
				}
				if (qq(a[j], 1, b[j]) == rqq(a[j], 1, b[j])) {
					// debug << "!\n";
					add(ans, f[i][j][1]);
				}
				continue;
			}
			if (f[i][j][0]) {
				F(t, 1, n) if (i * 2 + b[j] + len[t] <= l) {
					int k = min(b[j], len[t]);
					if (qq(a[j], len[a[j]] - b[j] + 1, len[a[j]] - b[j] + k) == rqq(t, len[t] - k + 1, len[t])) {
						if (b[j] > k) add(f[i + k][j - k][0], f[i][j][0]);
						else if (len[t] > k) add(f[i + k][id[t][len[t] - k]][1], f[i][j][0]);
							else add(f[i + k][0][0], f[i][j][0]);
					}
				}
			}
			if (f[i][j][1]) {
				F(t, 1, n) if (i * 2 + b[j] + len[t] <= l) {
					int k = min(b[j], len[t]);
					if (qq(a[j], b[j] - k + 1, b[j]) == rqq(t, 1, k)) {
						if (b[j] > k) add(f[i + k][j - k][1], f[i][j][1]);
						else if (len[t] > k) add(f[i + k][id[t][len[t] - k]][0], f[i][j][1]);
							else add(f[i + k][0][0], f[i][j][1]);
					}
				}
			}
		}
	cout << ans;
	return 0;
}
/* why?
*/