#include<cstdio>
#include<cstring>
#include<vector>
#include<queue>
#include<stack>
#include<algorithm>
#include<cmath>
#include<climits>
#include<string>
#include<set>
#include<numeric>
#include<map>
#include<iostream>
using namespace std;
#define rep(i,n) for(int i = 0;i<((int)(n));i++)
#define reg(i,a,b) for(int i = ((int)(a));i<=((int)(b));i++)
#define irep(i,n) for(int i = ((int)(n)-1);i>=0;i--)
#define ireg(i,a,b) for(int i = ((int)(b));i>=((int)(a));i--)
typedef long long ll;
typedef pair<ll, ll> mp;
ll mod = 1e9+7;
ll inf = 1e18;

//WA

int main(void){
	ll n,w,dp[10010]={},dp2[10010]={},sum=0;
	dp[0]=1;
	cin>>n;
	rep(i,n){
		cin>>w;
		sum+=w;
		rep(i,10010)dp2[i]=dp[i];
		rep(i,10010){
			dp[i+w]+=dp2[i];
		}
	}
	if(sum%2==0 && dp[sum/2]>0){
		cout<<"possible"<<endl;
	}else{
		cout<<"impossible"<<endl;
	}
	return 0;
}