#include <iostream>
#include <vector>
#include <numeric>
#include <algorithm>

int ReadNum(){
    int n;
    std::cin>>n;
    std::cin.ignore();
    return n;
}

std::vector <int> SetNumVector(const int size){
    std::vector <int> v;
    for(int i=0; i<size; i++){
        v.push_back(ReadNum());
    }
    return v;
}

int main(){
    int count = ReadNum();
    std::vector<int>weight =SetNumVector(count);
    int weight_sum =std::accumulate(weight.begin(),weight.end(),0);

    if((weight_sum%2)!=0){
         printf("immpossible\n");
        return 0;
    }
    
    std::sort(weight.begin(),weight.end(),std::greater<int>());
    
    int t=weight[0];
    for(int i=1; i<weight.size(); i++){
        if(t+weight[i]<=(weight_sum/2)) t += weight[i];
    }
    
    (weight_sum/2)==t ? printf("possible\n") : printf("immpossible\n");
    return 0;
}