#include <stdio.h>
#include <string.h>
int uz[30][30],n,A[30],B[30],x;
FILE *g;
void citire(){
    int i;
    char a,b;
    freopen("nrcuv.in","r",stdin);
    scanf("%d %d\n",&n,&x);
    for(i=1;i<=x;i++){
       scanf("%c %c\n",&a,&b);
        uz[a-'a'][b-'a']=1;
    uz[b-'a'][a-'a']=1;
    }
}
int main(){
   g=fopen("nrcuv.out","w");
   citire();
   int i,j,k,suma;
   suma=0;
  // fprintf(g,"%d",x);
   for(i=0;i<=25;i++) {A[i]=1;B[i]=0;}
   for(i=2;i<=n;i++){
      for(j=0;j<=25;j++)
         for(k=0;k<=25;k++)
          if(!uz[j][k])
            B[j]+=A[k];
      memcpy(A,B,sizeof(B));
      //memset(B,0,sizeof(B));
   }
  for(i=0;i<=25;i++){
      suma+=A[i];
   //fprintf(g," %d ",A[i]);
  }
fprintf(g,"%d",suma);
return 0;
}