import static java.lang.Math.*;
import static java.util.Arrays.*;
import java.util.*;

public class Main {
	Scanner sc = new Scanner(System.in);
	
	int MOD = 1000000007;
	int L = 20;
	
	void run() {
		for (;;) {
			int N = sc.nextInt(), M = sc.nextInt(), K = sc.nextInt();
			if ((N|M|K) == 0) return;
			String[] from = new String[N], to = new String[N];
			for (int i = 0; i < N; i++) {
				from[i] = sc.next();
				to[i] = sc.next();
			}
			String[] kigo = new String[K];
			for (int i = 0; i < K; i++) kigo[i] = sc.next();
			sort(kigo);
			TreeSet<String> set = new TreeSet<String>();
			for (int i = 0; i < N; i++) {
				set.add(from[i]);
				set.add(to[i]);
			}
			String[] word = set.toArray(new String[0]);
			int wordN = word.length;
			int[] ss = new int[N], ts = new int[N];
			for (int i = 0; i < N; i++) {
				ss[i] = binarySearch(word, from[i]);
				ts[i] = binarySearch(word, to[i]);
			}
			set.clear();
			set.add("");
			for (int i = 0; i < K; i++) {
				for (int j = 0; j < kigo[i].length(); j++) set.add(kigo[i].substring(0, j + 1));
			}
			String[] pre = set.toArray(new String[0]);
			int preN = pre.length;
			int[] end = new int[preN];
			for (int i = 0; i < preN; i++) {
				for (int j = 0; j < pre[i].length(); j++) if (binarySearch(kigo, pre[i].substring(j)) >= 0) end[i]++;
			}
			int[][] nextC = new int[preN][26];
			for (int i = 0; i < preN; i++) {
				for (int j = 0; j < 26; j++) {
					String s = pre[i] + (char)('a' + j);
					while (binarySearch(pre, s) < 0) s = s.substring(1);
					nextC[i][j] = binarySearch(pre, s);
				}
			}
			int[][] nextW = new int[preN][wordN];
			int[][] endW = new int[preN][wordN];
			for (int i = 0; i < preN; i++) {
				for (int j = 0; j < wordN; j++) {
					int p = i, e = 0;
					for (char c : word[j].toCharArray()) {
						p = nextC[p][c - 'a'];
						e += end[p];
					}
					nextW[i][j] = p;
					endW[i][j] = e;
				}
			}
			int[][][][] dp = new int[L + 1][2][wordN][preN];
			for (int i = 0; i < wordN; i++) {
				if (endW[0][i] <= 1) dp[word[i].length()][endW[0][i]][i][nextW[0][i]]++;
			}
			for (int len = 1; len < M; len++) {
				int crt = len % (L + 1), last = (len + L) % (L + 1);
				for (int i = 0; i < wordN; i++) for (int j = 0; j < preN; j++) dp[last][0][i][j] = dp[last][1][i][j] = 0;
				for (int k = 0; k < 2; k++) {
					for (int i = 0; i < N; i++) {
						int s = ss[i], t = ts[i];
						for (int j = 0; j < preN; j++) {
							int num = dp[crt][k][s][j];
							if (num > 0) {
								int len2 = (len + word[t].length()) % (L + 1), j2 = nextW[j][t], k2 = k + endW[j][t];
								if (k2 <= 1) {
									dp[len2][k2][t][j2] += num;
									if (dp[len2][k2][t][j2] >= MOD) dp[len2][k2][t][j2] -= MOD;
								}
							}
						}
					}
				}
			}
			int crt = M % (L + 1);
			int res = 0;
			for (int i = 0; i < wordN; i++) for (int j = 0; j < preN; j++) {
				res += dp[crt][1][i][j];
				if (res >= MOD) res -= MOD;
			}
			System.out.println(res);
		}
	}
	
	public static void main(String[] args) {
		new Main().run();
	}
}