import java.util.Arrays; import java.util.LinkedList; import java.util.Queue; import java.util.Scanner; public class Main { // どんな個数でも錘の合計の半分の重さを達成できれば, 残りの錘も半分の重さである. public static void main(String[] args){ Scanner sc = new Scanner(System.in); final int N = sc.nextInt(); int[] arr = new int[N]; for(int i = 0; i < N; i++){ arr[i] = sc.nextInt(); } final int sum = Arrays.stream(arr).sum(); if(sum % 2 != 0){ System.out.println("impossible"); }else{ boolean[][] DP = new boolean[N + 1][sum + 1]; DP[0][0] = true; for(int i = 0; i < N; i++){ for(int j = sum - arr[i]; j >= 0; j--){ if(DP[i][j]){ DP[i + 1][j + arr[i]] = true; } } } boolean ok = false; for(int i = 0; i < N; i++){ if(DP[i][sum / 2]){ ok = true; break; } } System.out.println(ok ? "possible" : "impossible"); } } }