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

#define REP(i,a,b) for(i=a;i<b;i++)
#define rep(i,n) REP(i,0,n)

typedef long long ll;

int dp[11000];

int main(){

  int N, W;
  cin >> N;
  int sum = 0;
  dp[0] = 1;
  while(N--){
    cin >> W;
    sum += W;
    for(int i=10000; i>=0; i--) {
			if(dp[i]) dp[i+W] = 1;
		}
  }
  if(sum % 2 == 0 && dp[sum/2]) printf("possible\n"); else printf("impossible\n");
  return 0;
}