#include <algorithm>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <vector>
using namespace std;

int n;
const int N=100;
vector<int> w(N);
int sum=0;

int dp[101][5001];
//x番目に注目していて、現在の重さはy
int rec(int x, int y){
  if(x==n) return (y==sum/2);
  if(dp[x][y]>=0) return dp[x][y];

  int ret;
  if(y+w[x]>sum/2) ret = rec(x+1,y);
  else ret = rec(x+1,y) || rec(x+1, y+w[x]);
  return ret;
}

int main(int argc, char const *argv[]) {
  cin >>n;
  for(int i=0; i<n; ++i){
    scanf(" %d", &w[i]);
    sum += w[i];
  }

  memset(dp, -1, sizeof(dp));

  if(sum%2==0){
    int ret=rec(0, 0);
    if(ret==1) printf("possible\n");
    else printf("impposible\n");
  }
  else printf("impposible\n");
  return 0;
}