#include <fstream>

using namespace std;

int l[27][27],s[1001][27],sum;

int main()
{
    ifstream f("nrcuv.in");
    ofstream h("nrcuv.out");
    int n,i,j,k,m;
    char x,y;
    f>>n>>m;
    for(i=1;i<=m;i++){
        f>>x>>y;
        l[x-'a'+1][y-'a'+1]=1;
        l[y-'a'+1][x-'a'+1]=1;
    }
    for(i=1;i<=26;i++)
        s[1][i]=1;
    for(k=2;k<=n;k++)
        for(i=1;i<=26;i++)
            for(j=1;j<=26;j++){
                if(!l[i][j])s[k][i]+=s[k-1][j];
            }
    for(i=1;i<=26;i++)
        sum+=s[n][i];
    h<<sum;
    return 0;
}