use std::io::{self, Read};

#[derive(Debug)]
struct Input {
    n: i32,
    ws: Vec<i32>,
}

fn next_token(cin_lock: &mut io::StdinLock) -> String {
    cin_lock
        .by_ref()
        .bytes()
        .map(|c| c.unwrap() as char)
        .skip_while(|c| c.is_whitespace())
        .take_while(|c| !c.is_whitespace())
        .collect::<String>()
}

fn read_input(cin_lock: &mut io::StdinLock) -> Input {
    let n = next_token(cin_lock).parse().unwrap();
    let ws = (0..n)
        .map(|_| next_token(cin_lock).parse().unwrap())
        .collect();
    Input { n, ws }
}

fn has_subset_sum(sum: i32, ws: &[i32]) -> bool {
    let mut dp = vec![vec![false; sum as usize + 1]; ws.len() + 1];
    dp[0][0] = true;

    for (i, w) in ws.iter().enumerate() {
        for k in 0..=(sum as usize) {
            dp[i + 1][k] = dp[i][k];
            if k >= *w as usize {
                dp[i + 1][k] |= dp[i][k - (*w as usize)];
            }
        }
    }

    dp[ws.len()][sum as usize]
}

fn solve(input: Input, _cin_lock: &mut io::StdinLock) {
    let sum: i32 = input.ws.iter().sum();

    let possible = if sum % 2 != 0 {
        false
    } else {
        has_subset_sum(sum / 2, &input.ws)
    };

    println!("{}", if possible { "possible" } else { "impossible" });
}

fn main() {
    let cin = io::stdin();
    let mut cin_lock = cin.lock();

    let input = read_input(&mut cin_lock);
    solve(input, &mut cin_lock);
}