def first_Element(arr,n,k):
     
    count_map = {}; 
    for i in range(0, n): 
        if(arr[i] in count_map.keys()): 
            count_map[arr[i]] += 1
        else: 
            count_map[arr[i]] = 1
        i += 1
    for i in range(0, n):  
        if (count_map[arr[i]] == k): 
            return arr[i] 
        i += 1 
    return -1
def count_ways(n):
	 
	A = [0] * (n + 1) 
	B = [0] * (n + 1) 
	A[0] = 1
	A[1] = 0
	B[0] = 0
	B[1] = 1
	for i in range(2, n+1): 
		A[i] = A[i - 2] + 2 * B[i - 1] 
		B[i] = A[i - 1] + B[i - 2] 
	return A[n] 