#include <iostream>
#include <vector>
using namespace std;

/* dp[i][j]　は1~i番目までの重りを使って、重さの合計をjにできるかどうか*/
bool dp[201][10101];

int N;
int w[200];
int sum;

int main(void){
    // Your code here!
    cin >> N;
    
    for(int i = 0; i < N; i++) {
        
        cin >> w[i];
        sum += w[i];
    }
    
    for(int i = 0; i <= 200; i++) for(int j = 0; j<=10000; j++) dp[i][j] = false;
    dp[0][0] = true;
    
    
    
    if(sum % 2 == 1) {
        cout << "impossible" << endl;
        return 0;
    }
    
    for(int i = 0; i < N; i++){
        for(int j = 0; j <= 10000; j++){
            if(!dp[i][j]) continue;
            dp[i+1][j + w[i]] = true; 
            dp[i+1][j] = true;
        }
    }
    
    if(dp[N][sum /2]) cout << "possible" << endl;
    else cout << "impossible" << endl;
    return 0;
    
}