#include <bits/stdc++.h>
using namespace std;
//#define FOR(i, n) for(int i = 0; i < (n); ++i)
#define f first
#define s second
#define pb push_back
#define all(x) x.begin(), x.end()
#define vi vector<int>
#define sz(x) ((int)(x).size())
typedef long long ll;
#define FOR2(i,b,e) for(int i=(b); i<=(e); i++)
#define SIZE(x) ((int)x.size())
const int N=110;

const int mod=1e9+7;

int n, m;
vector<string> slowa;
bool usun[N];

int G[N][N], tab[N][N], pom[N][N]; 

const int K = 26;
int lit(char x){
	return x-'a';
}

struct Vertex{
	int next[K];
	int leaf = -1;
	int p = -1;
	char pch;
	int link = -1;
	int go[K];
	
	Vertex(int _p = -1, char ch='$'): p(_p), pch(ch){
		fill(begin(next), end(next), -1);
		fill(begin(go), end(go), -1);
	}
};

vector<Vertex> t(1);

void add_string(string const& s, int id){
	int v = 0;
	for(char ch: s){
		int c = lit(ch);
		if(t[v].next[c] == -1){
			t[v].next[c] = t.size();
			t.emplace_back(v, ch); 
		}
		v = t[v].next[c];
	}
	t[v].leaf = id;
}

int go(int v, char ch);

int get_link(int v){
	if(t[v].link == -1){
		if(v == 0 || t[v].p == 0){
			t[v].link = 0;
		}
		else{
			t[v].link = go(get_link(t[v].p), t[v].pch);
		}
	}
	return t[v].link;
}

int go(int v, char ch){
	int c = lit(ch);
	if(t[v].go[c] == -1){
		if(t[v].next[c] != -1){
			t[v].go[c] = t[v].next[c];
		}
		else{
			t[v].go[c] = v == 0 ? 0 : go(get_link(v), ch);
		}
	}
	return t[v].go[c];
}

bool pod(string &a, string &b){
	FOR2(i, 0, SIZE(b)-SIZE(a)){
		if(a == b.substr(i, SIZE(a))) return 1;
	}
	return 0;
}

void buduj(){
	for(int i = 0 ; i < sz(t); i++){
		if(t[i].leaf != -1){
			G[i][i] = 26;
		}
		else{
			for(char j = 'a'; j <= 'z'; j++){
				G[i][go(i, j)]++; 
			}
		}
	}
}

#define FOR FOR2

void kwadrac(){
	FOR(i, 0, N-1) FOR(j, 0, N-1) pom[i][j]=G[i][j];
	FOR(i, 0, N-1) FOR(j, 0, N-1) G[i][j]=0;
	FOR(i, 0, N-1){
		FOR(j, 0, N-1){
			FOR(k, 0, N-1){
				G[i][j]=(G[i][j]+(ll)pom[i][k]*pom[k][j])%mod;
			}
		}
	}
}

void domnoz(){
	FOR2(i, 0, N-1) FOR2(j, 0, N-1) pom[i][j]=tab[i][j];
	FOR2(i, 0, N-1) FOR2(j, 0, N-1) tab[i][j]=0;
	FOR2(i, 0, N-1){
		FOR2(j, 0, N-1){
			FOR2(k, 0, N-1){
				tab[i][j]=(tab[i][j]+(ll)pom[i][k]*G[k][j])%mod;
			}
		}
	}
}

void poteguj(int exp){
	FOR2(i, 0, N-1) tab[i][i]=1;
	while(exp){
		if(exp&1) domnoz();
		kwadrac();
		exp>>=1;
	}
}

int pov(int base, int exp){
	int ret=1;
	while(exp){
		if(exp&1) ret=((ll)ret*base)%mod;
		base=((ll)base*base)%mod;
		exp>>=1;
	}
	return ret;
}

int main(){
	std::ios_base::sync_with_stdio(false);
	std::cin.tie(0);
	cin>>n>>m;
	int sum = 0;
	FOR2(i, 1, m){
		int a;
		string s;
		cin>>a>>s;
		sum += a;
		slowa.pb(s);
	}
	assert(sum <= 100);
	sort(slowa.begin(), slowa.end());
	slowa.erase(unique(slowa.begin(), slowa.end()), slowa.end());
	FOR(i, 0, SIZE(slowa)-1){
		FOR2(j, 0, SIZE(slowa)-1){
			if(i!=j && pod(slowa[i], slowa[j])) usun[j]=1; 
		}
	}
	FOR2(i, 0, SIZE(slowa)-1){
		if(!usun[i]) add_string(slowa[i], i+1);
	}
	buduj();
	/*FOR(i, 0, 3){
		FOR(j, 0, 3){
			cout<<G[i][j]<<' ';
		}
		cout<<endl;
	}*/
	poteguj(n);
	int ans=0;
	FOR(i, 1, sz(t)-1){
		if(t[i].leaf != -1){
			ans=(ans+tab[0][i])%mod;
		}
	}
	assert(((pov(26, n)-ans)%mod+mod)%mod >= 0);
	assert(((pov(26, n)-ans)%mod+mod)%mod < mod);
	cout<<((pov(26, n)-ans)%mod+mod)%mod<<'\n';
	return 0;
}