"""
Logic:
Is to keep track of  first maximum and
second maximum
"""
def max_second_num_from_arr(arr):
    if len(arr) < 2:
        return "-1"
    first_max = max(arr[0], arr[1])
    second_max = min(arr[0], arr[1])

    for i in range(2, len(arr)):
        if arr[i] > first_max:
            second_max = first_max
            first_max = arr[i]
        else:
            if arr[i] > second_max:
                second_max = arr[i]
    if first_max == second_max:
        second_max = "-1"
    return second_max