import java.util.HashMap;

import java.util.Map;

public class TwoSum

{

Map<Integer, Integer> _map = new HashMap();

/** Initialize your data structure here. */

public TwoSum()

{

}

/** Add the number to an internal data structure.. */

public void add( int number )

{

if ( _map.containsKey( number ) )

_map.put( number, _map.get( number ) + 1 );

else

_map.put( number, 1 );

}

/** Find if there exists any pair of numbers which sum is equal to the value. */

public boolean find( int value )

{

for ( int k : _map.keySet() )

{

if ( _map.containsKey( value - k ) )

{

if ( k * 2 == value && _map.get( k ) > 1 )

return true;

else if ( k * 2 != value )

return true;

}

}

return false;

}

}

/**

* Your TwoSum object will be instantiated and called as such:

* TwoSum obj = new TwoSum();

* obj.add(number);

* boolean param_2 = obj.find(value);

*/