#include <iostream>
#include <vector>
#include <cstdio>
using namespace std;

char q, w;
int n, m;
int a[1002][28];
bool ver[30][30];

int main()
{
    freopen("nrcuv.in", "r", stdin);
    freopen("nrcuv.out", "w", stdout);
    scanf("%d%d", &n, &m);
    for(int i = 1; i <= m; i++)
    {
        scanf("%c %c\n", &q, &w);
        ver[q - 'a' + 1][w - 'a' + 1] = 1;
        ver[w - 'a' + 1][q - 'a' + 1] = 1;
    }

    for(int i = 1; i <= 28; i++)
        a[1][i] = 1;
    for(int j = 1; j <= n; j++)
        for(int i = 1; i <= 26; i++)
            for(int k = 1; k <= 26; k++)
                if(ver[i][k] == 0 )
                    a[j][i] += a[j-1][k];
    int sum = 0;
    for(int i = 1; i <= 26; i++)
        sum += a[n][i];
    printf("%d", sum);
    return 0;
}