import math

def jumpSearch( arr , x , n ):
    step = math.sqrt(n)
    prev = 0
    while arr[int(min(step, n)-1)] < x:
        prev = step
        step += math.sqrt(n)
        if prev >= n:
            return -1
    while arr[int(prev)] < x:
        prev += 1
        if prev == min(step, n):
            return -1
    if arr[int(prev)] == x:
        return prev

    return -1
arr = [ 0, 1, 1, 2, 3, 5, 8, 13, 21,
    34, 55, 89, 144, 233, 377, 610 ]
x = 55
n = len(arr)


index = jumpSearch(arr, x, n)

print("Number" , x, "is at index" ,"%.0f"%index)