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

typedef long long ll;
typedef double lf;
typedef pair <int, int> pii;
typedef pair <ll, ll> pll;

#define TRACE(x) cerr << #x << ' ' << x << endl
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define REP(i, n) FOR(i, 0, n)
#define _ << ' ' <<

#define fi first
#define sec second
#define se second
#define mp make_pair
#define pb push_back

const int MAXN = 110;
const int MOD = 1e9 + 7;
int a[MAXN][MAXN], tmp[MAXN][MAXN], sol[MAXN][MAXN];

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);

  int n, q;
  cin >> n >> q;
  
  set<string> S, T;
  vector<string> V;
  for (int i = 0; i < q; i++) {
    int len;
    cin >> len;
    string s;
    cin >> s;
    S.insert(s);
  }
  for (string s : S) {
    for (int j = 0; j < (int)s.length(); j++) {
      string t = s.substr(0, j);
      if (!S.count(t)) T.insert(t);
    }
  }
  for (string s : T) V.push_back(s);
  int m = V.size();

  for (int i = 0; i < m; i++) {
    string s = V[i];
    for (char c = 'a'; c <= 'z'; c++) {
      string t = s + c;
      if (S.count(t)) continue;
      while (!T.count(t)) t = t.substr(1);
      int j = 0;
      while (V[j] != t) j++;
      a[j][i]++;
    }
  }

  for (int i = 0; i < m; i++)
    for (int j = 0; j < m; j++)
      if (i == j) sol[i][j] = 1;
      else sol[i][j] = 0;

  for (int exp = 0; exp < 32; exp++) {
    if ((1 << exp) & n) {
      for (int i = 0; i < m; i++)
        for (int j = 0; j < m; j++) {
          tmp[i][j] = 0;
          for (int k = 0; k < m; k++)
            tmp[i][j] = (tmp[i][j] + (ll)a[i][k] * sol[k][j]) % MOD;
        }

      for (int i = 0; i < m; i++)
        for (int j = 0; j < m; j++) 
          sol[i][j] = tmp[i][j];
    }

    for (int i = 0; i < m; i++)
      for (int j = 0; j < m; j++) {
        tmp[i][j] = 0;
        for (int k = 0; k < m; k++)
          tmp[i][j] = (tmp[i][j] + (ll)a[i][k] * a[k][j]) % MOD;
      }

    for (int i = 0; i < m; i++)
      for (int j = 0; j < m; j++)
        a[i][j] = tmp[i][j];
  }

  int total = 0;
  for (int i = 0; i < m; i++) total = (total + sol[i][0]) % MOD;
  cout << total;

  return 0;
}