#include <bits/stdc++.h>
using namespace std;

#define FOR(i,l,r) for(int i = (int) (l);i < (int) (r);i++)
template<typename T> bool chmax(T& a,const T& b){ return a < b ? (a = b,true) : false; }
template<typename T> bool chmin(T& a,const T& b){ return b < a ? (a = b,true) : false; }
typedef long long ll;

int N;
bool dp [101] [10001];

int main()
{
	scanf("%d",&N);
	vector<int> A(N);
	FOR(i,0,N){
		scanf("%d",&A [i]);
	}

	dp [0] [0] = true;
	FOR(i,0,N) FOR(j,0,10001) if(dp [i] [j]){
		dp [i + 1] [j] = true;
		dp [i + 1] [j + A [i]] = true;
	}

	int sum = accumulate(A.begin(),A.end(),0);
	if(sum % 2){
		puts("impossible");
	}
	else if(dp [N] [sum / 2]){
		puts("possible");
	}
	else{
		puts("impossible");
	}

	return 0;
}