#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <array>
#include <map>

using namespace std;

typedef long double ld;
typedef long long ll;

const int MAXN = 105, MOD = 1e9 + 7;

template<class T, int N> struct Matrix {
	typedef Matrix M;
	array<array<T, N>, N> d{};
	M operator*(const M& m) const {
        M a;
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < N; j++) {
                for (int k = 0; k < N; k++) {
                    a.d[i][j] += (d[i][k]*m.d[k][j])%MOD;
                    a.d[i][j] %= MOD;
                }
            }
        }
        return a;
	}
	vector<T> operator*(const vector<T> &vec) const {
        vector<T> ret(N);
        for (int i = 0; i < N; i++) {
            for (int j = 0; j < N; j++) {
                ret[i] += (d[i][j] * vec[j]) % MOD;
                ret[i] %= MOD;
            }
        }
        return ret;
	}
	M operator^(ll p) const {
        M a, b(*this);
        for (int i = 0; i < N; i++) {
            a.d[i][i] = 1;
        }
        while (p) {
            if (p & 1) a = a * b;
            b = b * b;
            p >>= 1;
        }
        return a;
	}
};

int n, q, ans;
int nxt_node = 1;
int par[MAXN];
char parc[MAXN];
bool banned[MAXN];
map<char, int> nxt[MAXN];

void add(int u, string &s, int i) {
    if (i == s.size()) {
        banned[u] = true;
        return;
    }

    char c = s[i];

    if (nxt[u].count(c) == 0) {
        par[nxt_node] = u;
        parc[nxt_node] = c;
        nxt[u][c] = nxt_node++;
    }

    add(nxt[u][c], s, i + 1);
}

int find(int u, string &s, int i) {
    if (i == s.size())
        return u;

    char c = s[i];

    if (nxt[u].count(c) == 0)
        return -1;

    return find(nxt[u][c], s, i + 1);
}

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

    cin >> n >> q;

    for (int i = 0; i < q; i++) {
        int l;
        string s;
        cin >> l >> s;
        add(0, s, 0);
    }

    Matrix<ll, MAXN> mat;

    for (int i = 0; i < nxt_node; i++) {
        if (banned[i]) continue;

        string s = "";

        int j = i;
        while(j != 0) {
            s.push_back(parc[j]);
            j = par[j];
        }

        reverse(s.begin(), s.end());

        for (char c = 'a'; c <= 'z'; c++) {
            s.push_back(c);

            for (int j = 0; j <= s.size(); j++) {
                int x = find(0, s, j);

                if (x != -1) {
                    mat.d[i][x]++;
                    break;
                }
            }

            s.pop_back();
        }
    }

    mat = mat^n;

    for (int i = 0; i < nxt_node; i++) {
        if (!banned[i])
            ans = (ans+mat.d[0][i]) % MOD;
    }

    cout << ans << endl;

	return 0;
}