#include <iostream>
#include <algorithm>
#include <vector>
#include <cstdio>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)

//dp[i番目までのおもりを見た時][左側の重さ] := (trueならある)
bool dp[101][10001];
int main(void){
	rep(i, 101)rep(j, 10001) dp[i][j] = false;
	int n; cin >> n;
	vector<int> w(n);
	rep(i, n)cin >> w[i];

	int sum = 0;
	rep(i, n) sum += w[i];
	if(sum % 2 == 1){
		printf("impossible\n");
		return 0;
	}

	dp[0][0] = true;
	for (int i = 0; i < n ; ++i){
		for (int j = 0; j <= 10000; ++j){
			if(dp[i][j] == true){
				dp[i + 1][j + w[i]] = true;
				dp[i + 1][j] = true;
			}
		}
	}

	if(dp[n][sum / 2] == true) printf("possible\n");
	else printf("impossible\n");
	return 0;
}