#include<stdio.h>
long n,m,i,a1,a2,f['z'+5]['z'+5],ss,s[1005]['z'+5];
int main()
{
 freopen("nrcuv.in","r",stdin);
 freopen("nrcuv.out","w",stdout);
 scanf("%ld%ld\n",&n,&m);
 for(i=1;i<=m;++i)
    {scanf("%c %c\n",&a1,&a2);
     f[a1][a2]=1;
     f[a2][a1]=1;}
 for(a1='a';a1<='z';++a1)s[1][a1]=1;
 for(i=1;i<n;++i)
    for(a1='a';a1<='z';++a1)
       for(a2='a';a2<='z';++a2)
          if(!f[a1][a2])s[i+1][a2]+=s[i][a1];
 for(a1='a';a1<='z';++a1)ss+=s[n][a1];
 printf("%ld\n",ss);
 return 0;
}