#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;
vector<vector<int>> memo( 100 + 1, vector<int>( 10000 + 1, -1 ) );
int N, total, res;
vector<int> vc;
bool dfs( int i, int x )
{
    if( i == 0 )
    {
        return x == 0;
    }
    if( x < 0 )
    {
        return false;
    }
    int &res = memo[ i ][ x ];
    if( res != -1 )
    {
        return res;
    }
    return ( res = dfs( i - 1, x ) || dfs( i - 1, x - vc[ i - 1 ] ) );
}
int main()
{
    cin >> N;
    vc.resize( N );
    for( auto &x : vc )
    {
        cin >> x;
    }
    total = accumulate( ALL( vc ), 0 );
    cout << ( dfs( N - 1, total / 2 ) && total % 2 == 0 ? "possible" : "impossible" ) << endl;
    return 0;
}