#include<bits/stdc++.h>
#define FOR(i,s,e) for(int i=(s); i<=(e); i++)
#define FORD(i,s,e) for(int i=(s); i>=(e); i--)
#define ALL(k) (k).begin(),(k).end()
#define e1 first
#define e2 second
#define pb push_back

#define int long long


using namespace std;
string inslo[105], slo[105];
int pocz[105], block[105];
int mac[105][105];
bool srt(string &a, string &b)
{
	return a.size() < b.size();
}
const int N = 103, mod = 1000000007;
struct macierz
{
	int t[105][105];
	macierz() {
		for (int i=0; i<N; i++)
			for (int j=0; j<N; j++)
				t[i][j]=0;
	}
};
macierz mnoz(macierz &a, macierz &b)
{
	macierz res;
	for (int i=0; i<N; i++)
	{
		for (int j=0; j<N; j++)
		{
			for (int h=0; h<N; h++)
			{
				res.t[i][j] += a.t[i][h] * b.t[h][j];
				res.t[i][j] %= mod;
			}
		}
	}
	return res;
}
macierz neutral()
{
	macierz res;
	for (int i=0; i<N; i++)
		res.t[i][i]=1;
	return res;
}
macierz normal()
{
	macierz res;
	for (int i=0; i<N; i++)
	{
		for (int j=0; j<N; j++)
		{
			res.t[i][j]=mac[i][j];
		}
	}
	return res;
}
macierz pot(macierz &a, int b) //&
{
	if (b == 0)
		return neutral();
	macierz res2 = pot(a, b/2);
	macierz res3 = mnoz(res2, res2);
	macierz res;
	if (b%2==1)
		res = mnoz(res3, a);
	else
		res = res3;
	return res;
}
bool contains(string &a, string &b)
{
	for (int i=0; i<(int)b.size(); i++)
	{
		int ok = 1;
		for (int j=0; j<(int)a.size(); j++)
		{
			if (j+i >= (int)b.size() || a[j] != b[j+i])
			{
				ok=0;
				break;
			}
		}
		if (ok == 1)
			return true;
	}
	return false;
}
const int MAXN = 111;

int ls[MAXN];
char a[MAXN][MAXN];
int confid[MAXN];
int confpos[MAXN];
char confval[MAXN][MAXN];

macierz chgs;

int32_t main()
{
	int n, q;scanf("%lld%lld", &n,&q);
	chgs.t[0][0] = 26; // 0 - rubbish
	
	
	int curconf = 1;
	FOR(i,1,q){
		int l; scanf("%lld", &l);
		ls[i] = l;
		scanf("%s", a[i]);
		FOR(j,0,l-1){
			curconf++;
			confid[curconf] = i;
			confpos[curconf] = j+1;
			FOR(k,0,j-1) confval[curconf][k] = a[i][k];
			reverse(confval[curconf], confval[curconf] + j);
		}
	}
	FOR(c1,1,curconf){
		for(char let = 'a'; let <= 'z'; let++){
			int best = 1;
			int len = 0;
			FOR(c2, 2, curconf){
				if(c2 == c1) continue;
				int l1 = confpos[c1], l2 = confpos[c2];
				if (l2 > l1 + 1) continue;
				if(confval[c2][0] != let) continue;
				bool ok = true;
				FOR(i, 1, l2-1){
					if (confval[c2][i] != confval[c1][i-1]){
						ok = false;
						break;
					}
				}
				if (!ok) continue;
				if (l2 == ls[confid[c2]]){
					best = 0;
					break;
				}
				if (l2 > len){
					best = c2;
					len = l2;
				}
			}
			chgs.t[c1][best]++;
		}
	}
	macierz odp = pot(chgs, n);
	macierz start;
	start.t[1][1] = 1;
	macierz ans = mnoz(start, odp);
	int finalans = 0;
	FOR(i,1, curconf){
		finalans += ans.t[1][i];
		finalans %= mod;
	}
	printf("%lld\n", finalans);
				
		
		
		
	
	
}