#include <iostream>
#include <algorithm>
#include <cmath>
#include <vector>
#include <complex>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>
#include <iomanip>
#include <assert.h>
#include <array>
#include <cstdio>
#include <cstring>
#include <random>
#include <functional>
#include <numeric>
#include <bitset>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)
#define all(c) (c).begin(), (c).end()
#define zero(a) memset(a, 0, sizeof a)
#define minus(a) memset(a, -1, sizeof a)
#define minimize(a, x) a = std::min(a, x)
#define maximize(a, x) a = std::max(a, x)

using ll  = long long;
int const inf = 1<<29;

void ng() {
  cout << "impossible\n"; exit(0);
}

void ok() {
  cout << "possible\n"; exit(0);
}

int main() {

  int N; cin >> N;
  int w[N], sum = 0; rep(i, N) cin >> w[i], sum += w[i];
  if(sum % 2) { ng(); }

  bool dp[101][10001]; zero(dp);
  dp[0][sum/2] = 1;
  rep(i, N) for(int j=sum/2; j>=w[i]; j--) {
    dp[i+1][j] |= dp[i][j];
    dp[i+1][j-w[i]] |= dp[i][j];
  }

  if(dp[N][0]) { ok(); } else { ng(); }

  return 0;
}