#include <bits/stdc++.h>
using namespace std;
#define REP(i,n) for(int i=0; i<(n); i++)
#define REP2(i,x,n) for(int i=x; i<(n); i++)
#define ALL(n) begin(n),end(n)
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
// loop DP 編
int main()
{
    int N;
    cin >> N;
    vector<int> vc( N );
    for( auto &x : vc )
    {
        cin >> x;
    }
    int total = accumulate( ALL( vc ), 0 );
    vector<vector<int>> dp( 100 + 1, vector<int>( 10000 + 1 ) );
    dp[ 0 ][ 0 ] = 1;
    for( int i = 1; i <= N; i++ )
    {
        for( int j = 0; j <= total; j++ )
        {
            if( 0 <= j - vc[ i - 1 ] )
            {
                dp[ i ][ j ] = dp[ i - 1 ][ j ] || dp[ i - 1 ][ j - vc[ i - 1 ] ];
            }
            else
            {
                dp[ i ][ j ] = dp[ i - 1 ][ j ];
            }
        }
    }
    cout << ( dp[ N - 1 ][ total / 2 ] && total % 2 == 0 ? "possible" : "impossible" ) << endl;
    return 0;
}