def binary_search(sorted_list, target):
    low = 0
    high = len(sorted_list) - 1

    while low <= high:
        mid = low + (high - low) // 2
        if sorted_list[mid] == target:
            return mid
        elif sorted_list[mid] < target:
            low = mid + 1
        else:
            high = mid - 1

    return -1


numbers = [2, 5, 8, 12, 16, 23, 38, 45, 56, 72]
print(binary_search(numbers, 23))   # 5
print(binary_search(numbers, 100))  # -1