#include <fstream>
#include <string>
using namespace std;
ifstream in("nrcuv.in");
ofstream out("nrcuv.out");
int n,m,z,h,b[27][27],a[1001][27],i,j,s,l;
char y,x,d;
int main()
{
	in>>n>>m;
	in>>d;
	for(i=1;i<=m;i++)
	{
		in>>x>>d>>y;
		in>>d;
		z=x-96;
		h=y-96;
		b[z][h]=1; b[h][z]=1;
	}
	for (i=1;i<=26;i++)a[1][i]=1;
	
	for (i=2;i<=n;i++)
		for (j=1;j<=26;j++)
		{
			s=0;
			for (l=1;l<=26;l++)
				if (b[j][l]==0) s=s+a[i-1][l];
			a[i][j]=s;
		}
	s=0;	
	for (i=1;i<=26;i++) s=s+a[n][i];
	out<<s;
	return 0;
}