#include <cstdio>
#define NRCUV 26
#define NMAX 1023
using namespace std;
FILE *fin, *fout;
int n, m, d[NMAX][NRCUV+3], sum;
bool check[NRCUV + 3][NRCUV + 3];
char x[3], y[3];
int main()
{
	fin = freopen("nrcuv.in", "r", stdin);
	fout = freopen("nrcuv.out", "w", stdout);
	scanf("%d%d", &n, &m);
	for(int i = 0; i< m; i++)
	{
		scanf("%s%s", x, y);
		check[x[0]-'a'][y[0]-'a'] = 1;
		check[y[0]-'a'][x[0]-'a'] = 1;
	}
	for(int i = 0; i< NRCUV; i++) d[1][i] = 1;
	for(int i = 2; i<= n; i++)
	{
		for(int j = 0; j< NRCUV; j++)
		{
			for(int k = 0; k< NRCUV; k++)
			{
				if(check[j][k]) continue;
				d[i][j] += d[i-1][k];
			}
		}
	}
	for(int i = 0; i< NRCUV; i++) sum+=d[n][i];
	printf("%d\n", sum);
	fclose(fin);
	fclose(fout);
	return 0;
}