//---------- begin union_find ----------
pub struct DSU {
    p: Vec<i32>,
}
impl DSU {
    pub fn new(n: usize) -> DSU {
        DSU { p: vec![-1; n] }
    }
    pub fn init(&mut self) {
        for p in self.p.iter_mut() {
            *p = -1;
        }
    }
    pub fn root(&self, mut x: usize) -> usize {
        assert!(x < self.p.len());
        while self.p[x] >= 0 {
            x = self.p[x] as usize;
        }
        x
    }
    pub fn same(&self, x: usize, y: usize) -> bool {
        assert!(x < self.p.len());
        assert!(y < self.p.len());
        self.root(x) == self.root(y)
    }
    pub fn unite(&mut self, x: usize, y: usize) -> Option<(usize, usize)> {
        assert!(x < self.p.len());
        assert!(y < self.p.len());
        let mut x = self.root(x);
        let mut y = self.root(y);
        if x == y {
            return None;
        }
        if self.p[x] > self.p[y] {
            std::mem::swap(&mut x, &mut y);
        }
        self.p[x] += self.p[y];
        self.p[y] = x as i32;
        Some((x, y))
    }
    pub fn parent(&self, x: usize) -> Option<usize> {
        assert!(x < self.p.len());
        let p = self.p[x];
        if p >= 0 {
            Some(p as usize)
        } else {
            None
        }
    }
    pub fn size(&self, x: usize) -> usize {
        assert!(x < self.p.len());
        let r = self.root(x);
        (-self.p[r]) as usize
    }
}
//---------- end union_find ----------
//https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 より
macro_rules! input {
    (source = $s:expr, $($r:tt)*) => {
        let mut iter = $s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
    ($($r:tt)*) => {
        let s = {
            use std::io::Read;
            let mut s = String::new();
            std::io::stdin().read_to_string(&mut s).unwrap();
            s
        };
        let mut iter = s.split_whitespace();
        input_inner!{iter, $($r)*}
    };
}

macro_rules! input_inner {
    ($iter:expr) => {};
    ($iter:expr, ) => {};
    ($iter:expr, $var:ident : $t:tt $($r:tt)*) => {
        let $var = read_value!($iter, $t);
        input_inner!{$iter $($r)*}
    };
}

macro_rules! read_value {
    ($iter:expr, ( $($t:tt),* )) => {
        ( $(read_value!($iter, $t)),* )
    };
    ($iter:expr, [ $t:tt ; $len:expr ]) => {
        (0..$len).map(|_| read_value!($iter, $t)).collect::<Vec<_>>()
    };
    ($iter:expr, chars) => {
        read_value!($iter, String).chars().collect::<Vec<char>>()
    };
    ($iter:expr, bytes) => {
        read_value!($iter, String).bytes().collect::<Vec<u8>>()
    };
    ($iter:expr, usize1) => {
        read_value!($iter, usize) - 1
    };
    ($iter:expr, $t:ty) => {
        $iter.next().unwrap().parse::<$t>().expect("Parse error")
    };
}

//

fn run() {
    input! {
        n: usize,
        e: [(usize1, usize1); n],
    }
    let mut dsu = DSU::new(n);
    let mut g = vec![vec![]; n];
    let mut back = (0, 0, 0);
    for (i, &(a, b)) in e.iter().enumerate() {
        if dsu.unite(a, b).is_some() {
            g[a].push((b, i));
            g[b].push((a, i));
        } else {
            back = (a, b, i);
        }
    }
    let mut depth = vec![0; n];
    let mut parent = vec![(n, n); n];
    let mut topo = vec![0];
    for i in 0..n {
        let v = topo[i];
        for &(u, k) in g[v].iter() {
            if u == parent[v].0 {
                continue;
            }
            parent[u] = (v, k);
            depth[u] = depth[v] + 1;
            topo.push(u);
        }
    }
    let (mut x, mut y, k) = back;
    let mut ans = vec![k];
    while x != y {
        if depth[x] < depth[y] {
            std::mem::swap(&mut x, &mut y);
        }
        ans.push(parent[x].1);
        x = parent[x].0;
    }
    ans.sort();
    let mut s = String::from(&format!("{}\n", ans.len()));
    for a in ans {
        s.push_str(&format!("{} ", a + 1));
    }
    s.pop();
    println!("{}", s);
}

fn main() {
    run();
}