// 5分くらいかも
#include <bits/stdc++.h>
using namespace std;

int dp[10010];
int main(){
	int N;
	cin >> N;
	int S = 0;
	dp[0] = 1;
	for(int i = 0 ; i < N ; i++){
		int w;
		cin >> w;
		S += w;
		for(int j = 10000 ; j >= w ; j--) 
			dp[j] |= dp[j-w];
	}
	if( S % 2 == 0 && dp[S/2] ) cout << "possible" << endl;
	else cout << "impossible" << endl;
	
}