#![allow(unused_imports, unused_macros, dead_code)]

macro_rules! min {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        it.next().map(|z| it.fold(z, |x, y| min!(x, y)))
    }};
    ($x:expr) => ($x);
    ($x:expr, $($ys:expr),*) => {{
        let t = min!($($ys),*);
        if $x < t { $x } else { t }
    }}
}
macro_rules! max {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        it.next().map(|z| it.fold(z, |x, y| max!(x, y)))
    }};
    ($x:expr) => ($x);
    ($x:expr, $($ys:expr),*) => {{
        let t = max!($($ys),*);
        if $x > t { $x } else { t }
    }}
}
macro_rules! ewriteln {
    ($($args:expr),*) => { let _ = writeln!(&mut std::io::stderr(), $($args),*); };
}
macro_rules! trace {
    ($x:expr) => { ewriteln!(">>> {} = {:?}", stringify!($x), $x) };
    ($($xs:expr),*) => { trace!(($($xs),*)) }
}
macro_rules! put {
    (.. $x:expr) => {{
        let mut it = $x.iter();
        if let Some(x) = it.next() { print!("{}", x); }
        for x in it { print!(" {}", x); }
        println!("");
    }};
    ($x:expr) => { println!("{}", $x) };
    ($x:expr, $($xs:expr),*) => { print!("{} ", $x); put!($($xs),*) }
}

const M: i64 = 1_000_000_007;

struct Permutation { n: usize, idx: usize }
impl Permutation {
    fn new(n: usize) -> Permutation {
        Permutation { n: n, idx: 0 }
    }
}
impl Iterator for Permutation {
    type Item = Vec<usize>;
    fn next(&mut self) -> Option<Vec<usize>> {
        let mut r = vec![0; self.n];
        let mut idx = self.idx;
        for k in 1..self.n {
            r[k] = idx % (k + 1);
            idx /= k + 1;
        }
        if idx > 0 { return None }
        r.reverse();
        let mut b = vec![true; self.n];
        b[r[0]] = false;
        for k in 1..self.n {
            let mut count = 0;
            for j in 0..self.n {
                if b[j] {
                    if count == r[k] {
                        r[k] = j;
                        b[j] = false;
                        break;
                    }
                    count += 1;
                }
            }
        }
        self.idx += 1;
        return Some(r)
    }
}

fn main() {
    let mut sc = Scanner::new();
    let n: usize = sc.cin();
    let m: usize = sc.cin();

    let mut g: Vec<Vec<bool>> = vec![vec![false; n]; n];
    for _ in 0..m {
        let a: usize = sc.cin();
        let b: usize = sc.cin();
        g[a-1][b-1] = true;
        g[b-1][a-1] = true;
    }

    let mut ans = 0;

    for p in Permutation::new(n) {
        let mut ok = true;
        if p[0] != 0 { continue }
        for i in 1..p.len() {
            if g[p[i-1]][p[i]] {
                // ok
            } else {
                ok = false;
            }
        }
        if ok { ans += 1 }
    }

    put!(ans);

}

use std::io::{self, Write};
use std::str::FromStr;
use std::collections::VecDeque;

struct Scanner { stdin: io::Stdin, buffer: VecDeque<String>, }
impl Scanner {
    fn new() -> Self { Scanner { stdin: io::stdin(), buffer: VecDeque::new() } }
    fn cin<T: FromStr>(&mut self) -> T {
        while self.buffer.len() == 0 {
            let mut line = String::new();
            let _ = self.stdin.read_line(&mut line);
            for w in line.split_whitespace() {
                self.buffer.push_back(String::from(w));
            }
        }
        self.buffer.pop_front().unwrap().parse::<T>().ok().unwrap()
    }
    fn chars(&mut self) -> Vec<char> { self.cin::<String>().chars().collect() }
    fn vec<T: FromStr>(&mut self, n: usize) -> Vec<T> { (0..n).map(|_| self.cin()).collect() }
}


Measured memory_bytes: 4352