#ifndef LOCAL
#pragma GCC optimize("O3")
#endif
#include <bits/stdc++.h>
using namespace std;
#define sim template <class c
#define mor > muu & operator<<(
#define ris return *this
#define R22(r) sim> typename enable_if<1 r sizeof(dud<c>(0)),muu&>::type operator<<(c g) {
sim> struct rge {c b, e;};
sim> rge<c> range(c i, c j) {return rge<c>{i, j};}
sim> auto dud(c*r)->decltype(cerr << *r);
sim> char dud(...);
struct muu {
	#ifdef LOCAL
	stringstream a;
	~muu() {cerr << a.str() << endl;}
	R22(<) a << boolalpha << g; ris;}
	R22(==) ris << range(begin(g), end(g));}
	sim mor rge<c> u) {
		a << "[";
		for (c i = u.b; i != u.e; ++i) 
			*this << ", " + 2 * (i == u.b) << *i;
		ris << "]";
	}
	sim, class b mor pair <b,c> r){ris << "(" << r.first << ", " << r.second << ")";}
	#else
	sim mor const c&){ris;}
	#endif
};
#define debug muu() << __FUNCTION__ << "#" << __LINE__ << ": "
#define imie(r...) "[" #r ": " << (r) << "] "
#define range(a, b) "[[" #a ", " #b "): " << range(a, b) << "] "
#define arr(a, i) "[" #a imie(i) ": " << a[i] << "] "
using ll = long long;
using ld = long double;
using pii = pair <int, int>;
const int mod = 1e9 + 7, nax = 102;
map <string, int> states;
set <string> banned;
char in[nax];
using matr = array<array <ll,nax>,nax>;
matr m, ans;
int A;
matr mul(const matr &a, const matr &b) {
	matr out;
	memset(&out, 0, sizeof(out));
	for (int i = 0; i < A; ++i) for (int j = 0; j < A; ++j)
		for (int k = 0; k < A; ++k)
			out[i][j] = (out[i][j] + a[i][k] * b[k][j]) % mod;
	return out;
}
int main() {
	int n, q;
	scanf("%d%d", &n, &q);
	for(int i = 0; i < q; ++i) {
		scanf("%*d%s", in);
		string str(in);
		int l = str.size();
		for (int j = 0; j <= l; ++j) {
			states.insert(make_pair(string(str.begin(), str.begin() + j), 0));
		}
		banned.insert(str);
	}
	debug << imie(states) imie(banned);
	int cou = 0;
	for (auto &x : states) x.second = cou++;
	debug << imie(states);
	for (auto &x : states) {
		if (banned.count(x.first)) continue;
		for (char c = 'a'; c <= 'z'; ++c) {
			string to = x.first + string(1, c);
			while (!states.count(to))
				to.erase(to.begin());
			debug << imie(x) imie(c) imie(to);
			if (!banned.count(to))
				m[x.second][states[to]]++;
		}
	}
	A = cou;
	//~ for (int i = 0; i < A; ++i)
		//~ debug << range(&m[i][0], &m[i][A]);
	int exp = n;
	for (int i = 0; i < A; ++i) ans[i][i] = 1;
	while (exp) {
		if (exp % 2) ans = mul(ans, m);
		m = mul(m, m);
		exp >>= 1;
	}
	ll out = 0;
	for (int i = 0; i < A; ++i)
		out += ans[0][i];
	out %= mod;
	printf("%lld\n", out);
}