#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define rep(i,n) for(int i=0;i<(n);i++) #define all(x) x.begin(), x.end() #define rall(x) x.rbegin(), x.rend() #define sz(x) ((int)(x).size()) #define pb push_back #define mod 1000000007 using ll = long long; using namespace std; ll gcd(ll a, ll b) {return b?gcd(b,a%b):a;} ll lcm(ll a, ll b) {return a/gcd(a,b)*b;} int main(){ int N; cin >> N; vector W(N); rep(i,N) cin >> W[i]; int sum = 0; rep(i,N) sum += W[i]; if(sum%2==1) { cout << "impossible" << endl; return 0; } else{ vector> dp(N+1,vector(sum+1,false)); rep(i,N+1)dp[i][0] = true; for(int i=1; i<=N; i++){ int w = W[i]; rep(j,sum){ if(dp[i-1][j] && j+w<=sum){ dp[i][j+w] = true; } } } rep(i,N+1){ if(dp[i][sum/2]){ cout << "possible" << endl; return 0; } } } cout << "impossible" << endl; return 0; }