#include #define rep(i,n) for(int i=0;i<(int)(n);i++) #define chmin(x,y) x = min((x),(y)); #define chmax(x,y) x = max((x),(y)); using namespace std; using ll = long long ; using P = pair ; using pll = pair; const int INF = 1e9; const long long LINF = 1e17; const int MOD = 1000000007; //const int MOD = 998244353; const double PI = 3.14159265358979323846; int main(){ int n; cin >> n; vector w(n); rep(i,n) cin >> w[i]; vector> dp(n+1,vector(10005,0)); int W = 0; rep(i,n) W += w[i]; dp[0][0] = 1; for(int i=1;i<=n;i++){ for(int j=0;j<10005;j++){ dp[i][j] = dp[i-1][j]; if(j-w[i-1]>=0) dp[i][j] += dp[i-1][j-w[i-1]]; if(dp[i][j]>0) dp[i][j] = 1; } } if(W%2==1) cout << "impossible" << endl; else{ if(dp[n][W/2]>0) cout << "possible" << endl; else cout << "impossible" << endl; } return 0; }