#![allow(unused_imports, unused_macros)]

use kyoproio::*;
use std::{
    collections::*,
    io::{self, prelude::*},
    iter,
    mem::{replace, swap},
};

fn main() -> io::Result<()> {
    std::thread::Builder::new()
        .stack_size(64 * 1024 * 1024)
        .spawn(|| {
            let stdin = io::stdin();
            let stdout = io::stdout();
            run(KInput::new(stdin.lock()), io::BufWriter::new(stdout.lock()))
        })?
        .join()
        .unwrap()
}

fn run<I: Input, O: Write>(mut kin: I, mut out: O) -> io::Result<()> {
    macro_rules! output { ($($args:expr),+) => { write!(&mut out, $($args),+)?; }; }
    macro_rules! outputln {
        ($($args:expr),+) => { output!($($args),+); outputln!(); };
        () => { output!("\n"); if cfg!(debug_assertions) { out.flush()?; } }
    }

    let n: usize = kin.input();
    let es: Vec<(usize, usize)> = kin.seq(n);
    let mut g = vec![Vec::new(); n + 1];
    for &(u, v) in &es {
        g[u].push(v);
        g[v].push(u);
    }
    let ll = LowLink::new(&g);
    let mut ans = Vec::new();
    for i in 0..n {
        let (u, v) = es[i];
        if !ll.is_bridge(u, v) {
            ans.push(i + 1);
        }
    }
    outputln!("{}", ans.len());
    for i in ans {
        output!("{} ", i);
    }
    outputln!();

    Ok(())
}

#[derive(Debug)]
pub struct LowLink<'a> {
    g: &'a [Vec<usize>],
    ord: Vec<usize>,
    low: Vec<usize>,
}
impl<'a> LowLink<'a> {
    pub fn new(g: &'a [Vec<usize>]) -> Self {
        let mut ll = Self {
            g,
            ord: vec![!0; g.len()],
            low: vec![!0; g.len()],
        };
        let mut id = 0;
        for u in 0..g.len() {
            if ll.ord[u] == !0 {
                ll.dfs(u, !0, &mut id);
            }
        }
        ll
    }
    fn dfs(&mut self, u: usize, p: usize, id: &mut usize) {
        self.ord[u] = *id;
        self.low[u] = *id;
        *id += 1;
        for &v in self.g[u].iter().filter(|&&v| v != p) {
            if self.ord[v] == !0 {
                self.dfs(v, u, id);
            }
            self.low[u] = self.low[u].min(self.low[v]);
        }
    }
    pub fn graph(&self) -> &[Vec<usize>] {
        &self.g
    }
    pub fn is_bridge(&self, mut u: usize, mut v: usize) -> bool {
        if self.ord[u] > self.ord[v] {
            swap(&mut u, &mut v)
        }
        self.ord[u] < self.low[v]
    }
}

// -----------------------------------------------------------------------------
pub mod kyoproio {
    use std::io::prelude::*;
    pub trait Input {
        fn str(&mut self) -> &str;
        fn input<T: InputParse>(&mut self) -> T {
            T::input(self)
        }
        fn iter<T: InputParse>(&mut self) -> Iter<T, Self> {
            Iter(self, std::marker::PhantomData)
        }
        fn seq<T: InputParse, B: std::iter::FromIterator<T>>(&mut self, n: usize) -> B {
            self.iter().take(n).collect()
        }
    }
    pub struct KInput<R> {
        src: R,
        buf: String,
        pos: usize,
    }
    impl<R: BufRead> KInput<R> {
        pub fn new(src: R) -> Self {
            Self {
                src,
                buf: String::with_capacity(1024),
                pos: 0,
            }
        }
    }
    impl<R: BufRead> Input for KInput<R> {
        fn str(&mut self) -> &str {
            loop {
                if self.pos >= self.buf.len() {
                    self.pos = 0;
                    self.buf.clear();
                    if self.src.read_line(&mut self.buf).expect("io error") == 0 {
                        return &self.buf;
                    }
                }
                let range = self.pos
                    ..self.buf[self.pos..]
                        .find(|c: char| c.is_ascii_whitespace())
                        .map(|i| i + self.pos)
                        .unwrap_or_else(|| self.buf.len());
                self.pos = range.end + 1;
                if range.end > range.start {
                    return &self.buf[range];
                }
            }
        }
    }
    pub struct Iter<'a, T, I: ?Sized>(&'a mut I, std::marker::PhantomData<*const T>);
    impl<'a, T: InputParse, I: Input + ?Sized> Iterator for Iter<'a, T, I> {
        type Item = T;
        fn next(&mut self) -> Option<T> {
            Some(self.0.input())
        }
    }
    pub trait InputParse: Sized {
        fn input<I: Input + ?Sized>(src: &mut I) -> Self;
    }
    impl InputParse for Vec<u8> {
        fn input<I: Input + ?Sized>(src: &mut I) -> Self {
            src.str().as_bytes().to_owned()
        }
    }
    macro_rules! from_str_impl {
        { $($T:ty)* } => {
            $(impl InputParse for $T {
                fn input<I: Input + ?Sized>(src: &mut I) -> Self {
                    src.str().parse::<$T>().expect("parse error")
                }
            })*
        }
    }
    from_str_impl! {
        String char bool f32 f64 isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128
    }
    macro_rules! tuple_impl {
        ($H:ident $($T:ident)*) => {
            impl<$H: InputParse, $($T: InputParse),*> InputParse for ($H, $($T),*) {
                fn input<I: Input + ?Sized>(src: &mut I) -> Self {
                    ($H::input(src), $($T::input(src)),*)
                }
            }
            tuple_impl!($($T)*);
        };
        () => {}
    }
    tuple_impl!(A B C D E F G);
    #[macro_export]
    macro_rules! kdbg {
        ($($v:expr),*) => {
            if cfg!(debug_assertions) { dbg!($($v),*) } else { ($($v),*) }
        }
    }
}