#include "bits/stdc++.h"
using namespace std;
#define rep(i,n) for(int i=0;i<n;i++)
#define REP(i,x,n) for(int i=x;i<n;i++)
#define ALL(v) (v).begin(),(v).end()
#define MP(a,b) make_pair(a,b)
typedef long long LL;
typedef pair<int, int> PI;
typedef vector<int> VI;
const LL MOD = 1000000007LL;
int W[100];
bool dp[10001];
int main() {
	int N;
	cin >> N;
	int sum = 0;
	rep(i, N) {
		cin >> W[i];
		sum += W[i];
	}
	dp[0] = 1;
	rep(i, N) {
		for (int j = 10000; j >= W[i]; j--) {
			dp[j] |= dp[j - W[i]];
		}
	}
	if (sum % 2 == 0 && dp[sum / 2]) {
		cout << "possible" << endl;
	}
	else {
		cout<<"impossible"<<endl;
	}
}