#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <map>
#include <set>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <string>
#include <time.h>
 
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define FFOR(i,a,b) for(int i=(a);i<=(b);i++)
#define REP(i,b) FOR(i,0,b)
#define RREP(i,b) FFOR(i,1,b)
#define PB push_back
#define F first
#define S second
#define BE(c) c.begin(),c.end()
using namespace std;
typedef long long LL;
typedef LL ut;
typedef long double ld;
typedef pair<ut,ut> pr;
typedef vector<pr> Vpr;
typedef vector<ut> VI;
typedef pair<ut,pr> ppr;
typedef priority_queue<pr,Vpr, greater<pr> > PQ;
const int SIZE=1e+5 + 1;
const ut INF=1<<30;
const ld eps=1e-6;
const LL mod=1e+9 + 7;

int N, W[128];
bool DP[11000];

int main() {
	cin.tie(0);
    ios::sync_with_stdio(false);
 	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 >= 0; --j)
 			DP[W[i] + j] |= DP[j];
 	if(sum % 2 == 0 && DP[sum / 2])
 		cout << "possible" << endl;
 	else
 		cout << "impossible" << endl;
	return 0;
}