#include<bits/stdc++.h>
using namespace std;

const int MAX_N = 100, MAX_SUM = 10000;
int dp[MAX_N+1][MAX_SUM+1];

int main(){
    int n, sw = 0; cin>>n;
    vector<int> w(n);
    for(int i=0;i<n;i++){
        cin>>w[i];
        sw += w[i];
    }

    if(sw%2){
        cout<<"impossible"<<endl;
        return 0;
    }

    dp[0][0] = 1;
    for(int i=1;i<=n;i++){
        for(int j=w[i-1];j<=sw;j++){
            dp[i][j] += dp[i-1][j-w[i-1]] + dp[i-1][j];
        }
    }

    for(int i=1;i<=n;i++){
        if(dp[i][sw/2]){
            cout<<"possible"<<endl;
            return 0;
        }
    }

    cout<<"impossible"<<endl;
    return 0;
}