#include using namespace std; #define REP(i, m, n) for (int i = (m); i < (int)(n); i++) #define REPS(i, m, n) for (int i = (m); i <= (int)(n); i++) #define rep(i, n) REP(i, 0, n) #define reps(i, n) for (int i = 0; i <= (int)(n); i++) #define rrep(i, x) for (int i = ((int)(x)-1); i >= 0; i--) #define rreps(i, x) for (int i = (int)(x); i >= 0; i--) #define all(x) (x).begin(), (x).end() #define rall(x) (x).rbegin(), (x).rend() #define pb push_back typedef long long ll; typedef pair P; const int inf = INT_MAX; const ll INF = 1LL << 60; const ll mod = 1e9 + 7; template inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; } template inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; } template void Fill(A (&array)[N], const T &val) { fill( (T*)array, (T*)(array+N), val ); } int dp[110][100010]; const int MAX = 100010; int main() { cin.tie(0); ios::sync_with_stdio(false); int N; cin >> N; vector W(N); int sum = 0; rep(i, N) { cin >> W[i]; sum += W[i]; } dp[0][0] = 1; rep(i, N) { rep(j, MAX) { if (dp[i][j] == 0) continue; dp[i+1][j+W[i]] += dp[i][j]; dp[i+1][j] += dp[i][j]; } } rep(i, MAX) { if (dp[N][i] == 2 && i * 2 == sum) { cout << "possible" << endl; return 0; } } cout << "impossible" << endl; return 0; }