LeetCode 170: Two Sum III - Data structure design

Design and implement a TwoSum class. It should support the following operations: add and find.
add - Add the number to an internal data structure.
find - Find if there exists any pair of numbers which sum is equal to the value.
For example,

add(1); add(3); add(5);
find(4) -> true
find(7) -> false

public class TwoSum {
    // <Number, Appearing Times of Number>
    private Map<Integer, Integer> map = new HashMap<>();

    public void add(int number) {
        if (map.containsKey(number))
	    map.put(number, map.get(number)+1);
	else
	    map.put(number, 1);
    }
    
    public boolean find(int value) {
	for (int i : map.keySet())
	{
	    int rest = value - i;
	        
	    if (map.containsKey(rest))
	    {
	        if (i != rest)
	            return true;
	                
	        if (i==rest && map.get(rest)>=2)
	            return true;
	    }
	}
	    
	return false;
    }
}