#include<bits/stdc++.h>
typedef long long ll;
typedef unsigned long long ull;
using namespace std;
#define pb push_back
int dy[]={0, 0, 1, -1, 1, 1, -1, -1};
int dx[]={1, -1, 0, 0, 1, -1, -1, 1};

#define FOR(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--)
#define mp make_pair
#define fi first
#define sc second
ll n;
ll w[200];
ll dp[100][20000];
int main(){
	cin >> n;
	REP(i,n) {
		cin >> w[i];
	}
	ll sum = 0;
	REP(i,n) {
		sum += w[i];
	}
	if(sum % 2 == 1) {
		cout << "impossible" << endl;
		return 0;
	}

	sum /= 2;

	dp[0][0] = true;
	FOR(i,1,n + 1) {
		REP(j,sum + 1) {
			if(0 <= j - w[i - 1]) {
				dp[i][j] = (dp[i - 1][j] || dp[i - 1][j - w[i - 1]]);
			}else {
				dp[i][j] = dp[i - 1][j];
			}
		}
	}
	if(dp[n][sum]) {
		cout << "possible" << endl;
	}else{
		cout << "impossible" << endl;
	}
	return 0;
}