文本生成器[JSOI2007]

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

inline int read() {
	int x = 0, f = 1; char ch = getchar();
	for (; ch > '9' || ch < '0'; ch = getchar()) if (ch == '-') f = -1;
	for (; ch <= '9' && ch >= '0'; ch = getchar()) x = (x << 3) + (x << 1) + (ch ^ '0');
	return x * f;
}

const int mod = 10007;
int n, m, dp[10005][205], ans;
char s[205];

struct AC_automaton{
	int fail[10005], ch[10005][30], tot;
	bool tag[10005];
	
	inline void insert(char *str, int len) {
		int x = 0;
		for (int i = 1; i <= len; i++) {
			if (!ch[x][str[i]-'A']) ch[x][str[i]-'A'] = ++tot;
			x = ch[x][str[i]-'A'];
		}
		tag[x] = 1;
	}
	
	inline void getfail() {
		queue<int> q;
		for (int i = 0; i < 26; i++) if (ch[0][i]) q.push(ch[0][i]);
		while (!q.empty()) {
			int x = q.front(); q.pop();
			tag[x] |= tag[fail[x]];
			for (int i = 0; i < 26; i++) {
				if (ch[x][i]) fail[ch[x][i]] = ch[fail[x]][i], q.push(ch[x][i]);
				else ch[x][i] = ch[fail[x]][i];
			}
		}
	}
	
	inline void DP() {
		memset(dp, 0, sizeof(dp));
		dp[0][0] = 1;
		for (int i = 0; i < m; i++) {
			for (int x = 0; x <= tot; x++) {
				for (int c = 0; c < 26; c++) {
					if (!tag[ch[x][c]]) {
						dp[ch[x][c]][i+1] = (dp[ch[x][c]][i+1] + dp[x][i]) % mod;
					}
				}
			}
		}
		ans = 1;
		for (int i = 1; i <= m; i++) ans = ans * 26 % mod;
		for (int x = 0; x <= tot; x++) {
			ans = (ans - dp[x][m] + mod) % mod;
		}
	}
} T;

int main() {
	n = read(), m = read();
	for (int i = 1; i <= n; i++) {
		scanf("%s", s + 1);
		T.insert(s, strlen(s + 1)); 
	}
	T.getfail();
	T.DP();
	printf("%d\n", ans);
	return 0;
}