#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
#define FOR(i,n) for(int i=0;i<(n);i++)
#define MOD 1000000007
#define all(x) (x).begin(),(x).end()
template<class T> inline bool chmax(T& a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T& a,T b){if(a>b){a=b;return 1;}return 0;}
template<class T> inline T GCD(T a,T b){T c;while(b!=0){c=a%b;a=b;b=c;}return a;}
template<class T> inline T LCM(T a,T b){return a/GCD(a,b)*b;}

int main(){
	int n;
	cin >> n;
	int w[110],sum=0;
	FOR(i,n){
		cin >> w[i+1];
		sum+=w[i+1];
	}

	bool dp[110][10010]={0};
	dp[0][0]=1;


	for(int i=1;i<=n;i++){
		for(int j=0;j<=10000;j++){
			if(j-w[i]>=0){
				if(dp[i-1][j] || dp[i-1][j-w[i]]){
					dp[i][j]=1;
				}
			}
		}
	}

	if(dp[n][sum/2] && sum%2==0){
		cout << "possible" << endl;
	}else{
		cout << "impossible" << endl;
	}




}