#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define rep1(i,n) for(int i=1;i<=(int)(n);i++)
#define all(c) c.begin(),c.end()
#define pb push_back
#define fs first
#define sc second
#define show(x) cout << #x << " = " << x << endl
#define chmin(x,y) x=min(x,y)
#define chmax(x,y) x=max(x,y)
using namespace std;
bool dp[10001];
int main(){
	int N,s=0;
	cin>>N;
	dp[0]=1;
	rep(i,N){
		int w;
		cin>>w;
		s+=w;
		rep(j,10001) if(dp[j]) dp[j+w]=1;
	}
	if(!dp[N/2]||s%2) cout<<"im";
	puts("possible");
}