#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <queue>
#include <utility>
using namespace std;

typedef pair<int, int> P;
typedef unsigned long long ll;

#define For(i, a, b) for(int i = (a); i < (b); i++)
#define Rep(i, n) For(i, 0, (n))

const int inf = 999999999;
const int mod = 1000000007;

bool dp[110][10010];

int main(){
	int n; cin >> n;
	int w[n], W = 0;
	Rep(i, n){
		cin >> w[i];
		W += w[i];
	}
	dp[0][0] = true;
	Rep(i, n) Rep(j, W + 1){
		if(j >= w[i]){
			if(dp[i][j - w[i]] || dp[i][j]) dp[i + 1][j] = true;
		}else{
			if(dp[i][j]) dp[i + 1][j] = true;
		}
	}
	if(W % 2 == 0){
		if(dp[n][W / 2] > 0) cout << "possible" << endl;
		else cout << "impossible" << endl;
	}else{
		cout << "impossible" << endl;
	}
	return 0;
}