def introTutorial(V, arr):
    # Write your code here
    
    start = 0
    end = len(arr) - 1
    
    while start <= end:
        mid = (start + end) // 2
        if arr[mid] == V:
            return mid
        elif arr[mid] > V:
            end = mid - 1
        else:
            start = mid + 1
    return -1