#include using namespace std; #define rep(i,n) for (int (i)=(0);(i)<(int)(n);++(i)) using ll = long long; using P = pair; using namespace std; template void vin(vector& v, int n) { v.resize(n); for (int i = 0; i < n; ++i) { cin >> v[i]; } } string pos = "possible", imp = "impossible"; int dp[101][101][101]; int N; int W[101]; int solve(int idx, int l, int r) { int& res = dp[idx][l][r]; if (~res) return res; if (idx >= N) { res = (l == r); } else { res = max(solve(idx+1, l+W[idx], r), solve(idx+1, l, r+W[idx])); } return res; } int main() { cin >> N; rep(i, N) cin >> W[i]; rep(i, 101) rep(j, 101) rep(k, 101) dp[i][j][k] = -1; cout << (solve(0, 0, 0) == 1 ? pos : imp) << endl; return 0; }