#include <fstream>
using namespace std;

ifstream in("nrcuv.in");
ofstream out("nrcuv.out");

bool comb[26][26];
int nr[3][26];

void nextLine(int cur, int stop)
{
    if (cur>stop) return;

    for(int i=1; i<=26; i++)
    {
        for(int j=1; j<=26; j++)
        {
            if(comb[i][j]==false) nr[2][i]+=nr[1][j];
        }
    }

    for(int i=1; i<=26; i++)
    {
        nr[1][i]=nr[2][i];
        nr[2][i]=0;
    }

    nextLine(cur+1, stop);
}

int main()
{
    int n,m;
    in>>n>>m;

    for(int i=1; i<=m; i++)
    {
        char a, b;
        in>>a>>b;

        comb[a-'a'+1][b-'a'+1] = true;
        comb[b-'a'+1][a-'a'+1] = true;
    }

    for(int i=1; i<=26; i++) nr[1][i]=1;

    nextLine(2, n);

    int s=0;
    for(int i=1; i<=26; i++) s+=nr[1][i];
    out<<s;

}