#include <cstdio>
using namespace std;

#define MAX_N 100
#define MAX_W 100

int N;
int W[MAX_N];
bool dp[MAX_N * MAX_W + 1];

int main() {
	scanf("%d", &N);
	for (int i = 0; i < N; i++) scanf("%d", W + i);
	
	int sum = 0;
	for (int i = 0; i < N; i++) sum += W[i];
	
	dp[0] = 1;
	for (int i = 0; i < N; i++) {
		for (int w = MAX_N * MAX_W; W[i] <= w; w--) {
			dp[w] = dp[w] | dp[w - W[i]];
		}
	}
	
	bool ispossible = 0;
	if (sum % 2 == 0 && dp[sum / 2]) ispossible = 1;
	
	printf("%s\n", ispossible ? "possible" : "impossible");
	
	return 0;
}