fn getline() -> String
{
	let mut inp: String = String::new();
	match std::io::stdin().read_line(&mut inp) {
		Ok(_) => inp.trim().to_string(),
		Err(e) => format!("{}", e),
	}
}

fn main()
{
	let mut inp: String = getline();
	inp = getline();
	let mut weight: Vec<i32> = Vec::new();
	let tmp: Vec<_> = inp.split(" ").collect();
	for x in tmp {
		match x.parse::<i32>() {
			Ok(var) => weight.push(var),
			Err(e) => println!("{}", e),
		}
	}
	let n: usize = weight.len() as usize;
	let mut half: i32 = weight.iter().fold(0, | half, a | half + a);
	
	if half % 2 == 1 {
		println!("impossible");
	}

	else {
		half /= 2;

		let mut dp = [0;6000];
		let mut nxt = [0;6000];
		dp[0] = 1;

		for k in 0..n as usize {
			for i in 0..half as usize {
				if dp[i] != 1 {
					continue;
				}

				nxt[i] = 1;
				if i as i32 + weight[k] <= half {
					nxt[i+weight[k] as usize] = 1;
				}
			}

			dp.copy_from_slice(&nxt);
		}

		if dp[half as usize] == 1 {
			println!("possible");
		}
		else {
			println!("impossible");
		}
	}
}