using namespace std;

#define MAX_N 4005
#define MAX_L 30

#include <stdio.h>
#include <fstream>

FILE *fin=fopen("nrcuv.in","r"),
     *fout=fopen("nrcuv.out","w");
     
int i,j,n,m,k;
char c1,c2;
long long v[MAX_N][MAX_L];
int o[MAX_L][MAX_L];
long long sol;
     
int main()
{
   fscanf(fin,"%d %d\n",&n,&m);
   memset(o,0,sizeof(o));
   for (i=1; i<=m; i++) {
    fscanf(fin,"%c %c\n",&c1,&c2);
    o[c1-96][c2-96]=1;
   }
   for (j=1; j<=26; j++)
    v[1][j]=1;
   for (i=1; i<=n; i++)
    for (j=1; j<=26; j++) 
     for (k=1; k<=26; k++)
      if (o[j][k]==0 && o[k][j]==0) v[i][j]+=v[i-1][k];  
   sol=0;   
   for (i=1; i<=26; i++)
    sol+=v[n][i];
   fprintf(fout,"%lld\n",sol);
   
   fclose(fin); fclose(fout);
   
   return 0;
}