#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 1000000001

int main(){
	int n;
	cin>>n;
	
	bitset<10005> B;
	B[0] = 1;
	int S  =0;
	rep(i,n){
		int w;
		cin>>w;
		S += w;
		B |= B<<w;
	}
	
	if(S%2==0&&B[S/2])cout<<"possible"<<endl;
	else cout<<"impossible"<<endl;
	
	return 0;
}