#include <stdio.h>

int n, m, a[1002][30], b[30][30];
long s;

int main()
{
	freopen("nrcuv.in","r",stdin);
	freopen("nrcuv.out","w",stdout);

	int i, j, k;
	char x, y;

	scanf("%d %d\n", &n, &m);

	for (i = 1; i <= m; i++)
	{
		scanf("%c %c\n",&x, &y);
		b[x-'a'+1][y-'a'+1] = b[y-'a'+1][x-'a'+1] = 1;
	}

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


	for (i = 2; i <= n; i++)
		for(j = 1; j <= 26; j++)
			for (k = 1; k <= 26; k++)
				if (!b[j][k]) a[i][j] += a[i-1][k];

	for (i = 1; i <= 26; i++) s+= a[n][i];
	printf("%d\n",s);
	return 0;
}