N = 11
g =[[0] * N for i in range(N)]
st = [False] * N
pos = [0] * N

def dfs(u):
    if u == n:
        if g[pos[n - 1]][pos[0]]:
            return 0
        return 1

    res = 0
    for i in range(1, n + 1):
        if not st[i] and not g[i][pos[u - 1]]:
            pos[u] = i
            st[i] = True
            res += dfs(u + 1)
            st[i] = False
    return res

n, m = map(int, input().split())
while m:
    m -= 1
    a, b = map(int, input().split())
    g[a][b] = True
    g[b][a] = True
pos[0] = 1
st[1] = True

print(dfs(1))