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