#define ll long long
#define ffor(i,a,b) for (int i=(a);i<(b);i++)
#define rfor(i,a,b) for (int i=(b)-1;i>=(a);i--)
#define rep(i,n) for (int i=0;i<(n);i++)
#define rrep(i,n) for (int i=(n)-1;i>=0;i--)
#include<iostream>
#include<iomanip>
#include<algorithm>
#include<cmath>
#include<string>
#include<stack>
#include<queue>
#include<vector>
#include<map>
#define SIZE 100001
#define MOD 1000000007
#define INF 100000000
using namespace std;
bool dp[101][SIZE];

//dp[i番目のとき][左側の重さ]
int main(){
	
	rep(i,101){
		rep(j,10001) dp[i][j] = false;
	}

	int n;
	vector<int> v(100);
	cin >> n;
	rep(i,n) cin >> v[i];

	int sum = 0;
	rep(i,n) sum += v[i];

	if(sum%2 == 1){
		cout << "impossible" << endl;
		return 0;
	}

	dp[0][0] = true;
	rep(i,n){
		rep(j,10001){
			if(dp[i][j]){//全パターンのメモを行う.
				//左側の天秤に入れる
				dp[i+1][j+v[i]] = true;
				//右側の天秤に入れる
				dp[i+1][j] = true;
			}
		}
	}
	
	cout << ((dp[n][sum/2])?"possible":"impossible")<<endl;
	return 0;
}