#include <iostream>
#include <fstream>

using namespace std;

ifstream fin("nrcuv.in");
ofstream fout("nrcuv.out");

int n, m, dp[1005][30], ans;
bool mat[30][30];

int main()
{
    fin >> n >> m;
    for(int i = 1; i <= m; i++)
    {
        char x, y;
        fin >> x >> y;
        mat[x-'a'+1][y-'a'+1]=true;
        mat[y-'a'+1][x-'a'+1]=true;
    }
    for(int i = 1; i <= 26; i++)
        dp[1][i]=1;
    for(int i = 2; i <= n; i++)
        for(int j = 1; j <= 26; j++)
            for(int k = 1; k <= 26; k++)
            {
                if(mat[j][k])
                    continue;
                dp[i][j]+=dp[i-1][k];
            }
    for(int i = 1; i <= 26; i++)
        ans+=dp[n][i];
    fout<<ans;
    return 0;
}