#include <algorithm>
#include <iostream>
#include <cstdio>
#include <map>
#include <numeric>
#include <cmath>
#include <set>
#include <sstream>
#include <string>
#include <vector>
#include <queue>
#include <complex>
#include <string.h>
using namespace std;

#define endl '\n'
#define all(v) (v).begin(), (v).end()
#define uniq(v) (v).erase(unique((v).begin(), (v).end()), (v).end())

typedef long long ll;
typedef pair<int, int> P;
typedef unsigned int uint;

const int inf = 1000000009;

bool solve(int n) {
    int w[n];
    int sum = 0;
    for (int i = 0; i < n; i++) {
	int v;
	scanf("%d", &v);
	sum += v;
	w[i] = v;
    }

    if (sum % 2 == 1) return false;
    bool can[sum+1];
    memset(can, false, sizeof(can));
    can[0] = true;
    for (int i = 0; i < n; i++) {
	for (int j = sum; j >= 0; j--) {
	    if (can[j])
		can[j+w[i]] = true;
	}
    }
    return can[sum/2];
}

int main() {
    int n;
    scanf("%d", &n);
    printf("%s\n", solve(n) ? "possible" : "impossible");
}