use std::io::BufRead;

pub struct StdinReader<R: BufRead> {
    pub buf_reader: R,
    pub buf: String,
}
impl<R: BufRead> StdinReader<R> {
    pub fn new(r: R) -> Self {
        StdinReader {
            buf_reader: r,
            buf: String::with_capacity(10000),
        }
    }
}

#[macro_export]
macro_rules! input {
    ($reader : expr, $t : ty) => { // one variable
        match &mut $reader {
            reader => {
                use std::io::BufRead;
                reader.buf_reader.read_line(&mut reader.buf).unwrap();
                let tmp_var: $t = reader.buf.trim().parse().unwrap(); 
                reader.buf.clear();
                tmp_var
            },
        }
    };
    ($reader : expr, $t0 : ty, $t1 : ty) => { // 2 tuple
        match &mut $reader {
            reader => {
                use std::io::BufRead;
                reader.buf_reader.read_line(&mut reader.buf).unwrap();
                let tmp_var: Vec<$t0> = reader.buf.trim().split_whitespace().map(|a| a.parse().unwrap()).collect();
                reader.buf.clear();
                (tmp_var[0], tmp_var[1])
            }
        }
    };
    ($reader : expr, $t0 : ty, $t1 : ty, $t2 : ty) => { // 3 tuple
        match &mut $reader {
            reader => {
                use std::io::BufRead;
                reader.buf_reader.read_line(&mut reader.buf).unwrap();
                let tmp_var: Vec<$t0> = reader.buf.trim().split_whitespace().map(|a| a.parse().unwrap()).collect();
                reader.buf.clear();
                (tmp_var[0], tmp_var[1], tmp_var[2])
            }
        }
    };
    ($reader : expr, $t : ty, $size : expr) => { // Vector
        match &mut $reader {
            reader => {
                use std::io::BufRead;
                reader.buf_reader.read_line(&mut reader.buf).unwrap();
                let tmp_var: $t = reader.buf.trim().split_whitespace().map(|a| a.parse().unwrap()).collect();
                reader.buf.clear();
                tmp_var
            }
        }
    };
}
fn creates_bit_patterns(digit: usize) -> Vec<Vec<usize>> {
    let until = usize::pow(2, digit as u32);
    let mut v = Vec::with_capacity(until);
    for num in 0..until {
        v.push(creates_bit_pattern(num, digit));
    }
    return v;
}
fn creates_bit_pattern(mut num: usize, digit: usize) -> Vec<usize> {
    let mut v = Vec::with_capacity(digit);
    for _ in 0..digit {
        v.push(num % 2);
        num /= 2;
    }
    return v;
}

#[derive(Debug, Hash)]
struct Edge {
    a: usize,
    b: usize,
}
impl Eq for Edge {}
impl PartialEq for Edge {
    fn eq(&self, other: &Self) -> bool {
        (self.a == other.a && self.b == other.b) || (self.b == other.a && self.a == other.b)
    }
}
impl Edge {
    fn new(a: usize, b: usize) -> Self {
        Edge { a: a, b: b, }
    }
    fn reverse(&self) -> Self {
        Edge {a: self.b, b: self.a, }
    }
}

fn main() {
    let handle = std::io::stdin();
    let mut r = StdinReader::new(handle.lock());
    let (n, m) = input!(r, usize, usize);
    let inf = std::usize::MAX;
    let mut dp: Vec<Vec<usize>> = vec![vec![0; n]; (2 as usize).pow(n as u32)];
    let mut edges: Vec<Vec<bool>> = vec![vec![false; n]; n];
    dp[1][0] = 1;
    for i in 0..m {
        let (a, b) = input!(r, usize, usize);
        edges[a-1][b-1] = true;
        edges[b-1][a-1] = true;
    }
    for i in 0..(2 as usize).pow(n as u32) {
        if creates_bit_pattern(i, n)[0] != 1 { continue; }
        for j in 0..n {
            if dp[i][j] == 0 { continue; }
            for k in 0..n {
                if creates_bit_pattern(i, n)[k] == 1 { continue; } // already visit (k) node.
                if edges[j][k] {
                    dp[i + (2 as usize).pow(k as u32)][k] += dp[i][j];
                }
            }
        }
    }
    println!("{:?}", dp[(2 as usize).pow(n as u32)-1].iter().skip(1).sum::<usize>());
}


Measured memory_bytes: 4352