// Giải thuật ac cho bài toán ac-dna\n#include <bits/stdc++.h>
using namespace std;

const int MOD = 1e9 + 7;
const int ALPHABET = 4;

int dnaIdx(char c) {
    if (c == 'A') return 0;
    if (c == 'C') return 1;
    if (c == 'G') return 2;
    return 3;
}

struct AhoCorasick {
    struct Node {
        int next[ALPHABET];
        int fail;
        bool bad;
        Node() {
            fill(next, next + ALPHABET, -1);
            fail = 0; bad = false;
        }
    };
    vector<Node> trie;
    AhoCorasick() { trie.emplace_back(); }
    void insert(const string& s) {
        int node = 0;
        for (char ch : s) {
            int c = dnaIdx(ch);
            if (trie[node].next[c] == -1) {
                trie[node].next[c] = trie.size();
                trie.emplace_back();
            }
            node = trie[node].next[c];
        }
        trie[node].bad = true;
    }
    void build() {
        queue<int> q;
        for (int c = 0; c < ALPHABET; c++) {
            if (trie[0].next[c] != -1) {
                trie[trie[0].next[c]].fail = 0;
                q.push(trie[0].next[c]);
            } else {
                trie[0].next[c] = 0;
            }
        }
        while (!q.empty()) {
            int u = q.front(); q.pop();
            if (trie[trie[u].fail].bad)
                trie[u].bad = true;
            for (int c = 0; c < ALPHABET; c++) {
                if (trie[u].next[c] != -1) {
                    trie[trie[u].next[c]].fail = trie[trie[u].fail].next[c];
                    q.push(trie[u].next[c]);
                } else {
                    trie[u].next[c] = trie[trie[u].fail].next[c];
                }
            }
        }
    }
};

int main() {
    // Doc du lieu dau vao
    ios::sync_with_stdio(false); cin.tie(0);
    int N, M; cin >> N >> M;
    AhoCorasick aho;
    for (int i = 0; i < M; i++) {
        string s; cin >> s;
        aho.insert(s);
    }
    aho.build();
    int S = aho.trie.size();
    vector<vector<int>> dp(N + 1, vector<int>(S, 0));
    dp[0][0] = 1;
    for (int i = 0; i < N; i++) {
        for (int u = 0; u < S; u++) {
            if (aho.trie[u].bad || dp[i][u] == 0) continue;
            for (int c = 0; c < ALPHABET; c++) {
                int v = aho.trie[u].next[c];
                if (aho.trie[v].bad) continue;
                dp[i + 1][v] = (dp[i + 1][v] + dp[i][u]) % MOD;
            }
        }
    }
    int ans = 0;
    for (int u = 0; u < S; u++)
        if (!aho.trie[u].bad)
            ans = (ans + dp[N][u]) % MOD;
    cout << ans << "\n";
    return 0;
}