#include <iostream>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <map>
#include <list>
#include <string>
#define _USE_MATH_DEFINES
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <bitset>
#define REP(i,n) for(int (i)=0;(i)<(n);(i)++)
#define RREP(i,n) for(int (i)=(n)-1;(i)>=0;(i)--)
#define debug(x) cout<<x<<endl
using namespace std;
typedef pair<int,int> P;
typedef priority_queue<int> maxpq;
typedef priority_queue<int,vector<int>,greater<int> > minpq;
typedef priority_queue<P> p_maxpq;
typedef priority_queue<P,vector<P>,greater<P> > p_minpq;
typedef vector<int> veci;
typedef vector<P> vecp;
typedef vector<string> vecs;
typedef long long int LL;
#define INF 2000000000
struct edge{int to,cost;};

int main(void) {
	int N;cin>>N;
	int W[100],weight = 0;
	REP(i,N) cin >> W[i];
	REP(i,N) weight += W[i];

	bool dp[10000] = {0};
	dp[0] = true;
	REP(i,N) {
		for(int j = weight/2-W[i];j >= 0;j--) {
			dp[j+W[i]] |= dp[j];
		}
	}
	if((weight%2==1)||!dp[weight/2]) cout <<"impossible"<<endl;
	else cout<<"possible"<<endl;
	return 0;
}