#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using Vi = vector<int>;
using Pii = pair<int,int>;
#define mp make_pair
#define pb push_back
#define x first
#define y second
#define rep(i,b,e) for(int i = (b); i < (e); i++)
#define each(a, x) for(auto& a : (x))
#define all(x) (x).begin(),(x).end()
#define sz(x) int((x).size())

#define tem template<class t,class u,class...w>
#define pri(x,y)tem auto operator<<(t& o, u a)->decltype(x,o) { o << y; return o; }
pri(a.print(), "{"; a.print(); "}");
pri(a.y, "(" << a.x << ", " << a.y << ")");
pri(all(a), "["; auto d=""; for (auto i : a) (o << d << i, d = ", "); o << "]");
void DD(...) {}
tem void DD(t s, u a, w... k) {
	for (int b = 44; *s && *s - b; cerr << *s++)
		b += ((*s == 41) - (*s == 40)) * 88;
	cerr << ": " << a << *s++; DD(s, k...);
}
tem vector<t> span(const t* a, u n) { return {a, a+n}; }
#ifdef LOC
#define deb(...) (DD("[,\b :] "#__VA_ARGS__, __LINE__, __VA_ARGS__), cerr << endl)
#else
#define deb(...)
#endif
#define DBP(...) void print() { DD(#__VA_ARGS__, __VA_ARGS__); }

struct Aho {
	enum{alpha = 26, first = 'a'};

	struct Node {
		int back, next[alpha], start = -1, end = -1, nmatches = 0;
		Node(int v) { memset(next, v, sizeof(next)); }
	};

	vector<Node> N;
	vector<int> backp;

	void insert(string& s, int j) {
		assert(!s.empty());
		int n = 0;
		each(c, s) {
			int& m = N[n].next[c-first];
			if (m == -1) {
				n = m = sz(N); N.emplace_back(-1);
			} else {
				n = m;
			}
		}
		if (N[n].end == -1) N[n].start = j;
		backp.push_back(N[n].end);
		N[n].end = j;
		N[n].nmatches++;
	}

	Aho(vector<string>& pat) {
		N.emplace_back(-1);
		rep(i, 0, sz(pat)) insert(pat[i], i);
		N[0].back = sz(N);
		N.emplace_back(0);

		queue<int> q;

		for (q.push(0); !q.empty(); q.pop()) {
			int n = q.front(), prev = N[n].back;
			rep(i, 0, alpha) {
				int &ed = N[n].next[i], y = N[prev].next[i];
				if (ed == -1) ed = y;
				else {
					N[ed].back = y;
					(N[ed].end == -1 ? N[ed].end : backp[N[ed].start]) = N[y].end;
					N[ed].nmatches += N[y].nmatches;
					q.push(ed);
				}
			}
		}
	}
};

constexpr ll MOD = 1000000007;

using Mat = vector<vector<ll>>;

Mat mul(Mat a, Mat b) {
	int n = sz(a);
	Mat c(n, vector<ll>(n));

	rep(i, 0, n) {
		rep(j, 0, n) {
			rep(k, 0, n) {
				c[i][j] += a[i][k] * b[k][j] % MOD;
				c[i][j] %= MOD;
			}
		}
	}

	return c;
}

Mat matPow(Mat a, ll e) {
	int n = sz(a);
	Mat t(n, vector<ll>(n));

	rep(i, 0, n) {
		t[i][i] = 1;
	}

	while (e > 0) {
		if (e % 2) {
			t = mul(t, a);
		}
		e /= 2;
		a = mul(a, a);
	}

	return t;
}

int main() {
	cin.sync_with_stdio(0); cin.tie(0);
	cout << fixed << setprecision(12);

	ll n;
	int q;
	cin >> n >> q;

	vector<string> elems(q);

	each(e, elems) {
		int l; cin >> l;
		cin >> e;
		//assert(sz(e) == l);
	}

	Aho aho(elems);

	int kek = sz(aho.N);
	Mat mat(kek, vector<ll>(kek));

	rep(i, 0, kek) {
		rep(a, 0, 26) {
			int j = aho.N[i].next[a];
			if (aho.N[j].nmatches == 0) {
				mat[i][j] += 1;
				mat[i][j] %= MOD;
			}
		}
	}

	Mat res = matPow(mat, n);
	ll ans = 0;

	//deb(mat, res);

	rep(i, 0, kek) {
		ans += res[0][i];
		ans %= MOD;
	}

	deb(MOD);

	ans %= MOD;
	if (ans < 0) ans += MOD;
	cout << ans << endl;
	return 0;
}