#include <bits/stdc++.h>
#define MAX_N 1001
using namespace std;
ifstream fin("nrcuv.in");
ofstream fout("nrcuv.out");

int N,M;

bool notPossible[28][28];
int DP[28][MAX_N];

int main() {
    fin >> N >> M;
    for (int i = 1; i <= M; i++) {
        char a,b;
        fin >> a >> b;
        a-='a';
        a++;
        b-='a';
        b++;
        notPossible[a][b] = true;
        notPossible[b][a] = true;
    }
    for (int i = 1; i <= 'z' - 'a' + 1; i++) {
        DP[i][1] = 1;
    }
    for (int i = 2; i <= N; i++) {
        for (int j = 1; j <= 'z' - 'a' + 1; j++) {
            for (int k = 1; k <= 'z' - 'a' + 1; k++) {
                if (notPossible[j][k]) {
                    continue;
                }
                DP[j][i] += DP[k][i-1];
            }
        }
    }
    unsigned long ans=0;
    for (int i = 1; i <= 'z' - 'a' + 1; i++) {
        ans += DP[i][N];
    }
    fout << ans;
    return 0;
}