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# gets the target sum
target = int(input())

# gets the numbers
input_list = input().split()

# stores numbers <= target sum in list <numbers>
numbers = []
for element in input_list:
    if int(element) <= target:
        numbers.append(int(element))

for i in range(len(numbers)):       # range(len(numbers) - indeces of items in the list <numbers>
    x = target - numbers[i]         # sum of which number <x> and i element of numbers, for short the number, gives <target>
    right_numbers = numbers[i+1:]   # list with numbers at right of the number in the list <numbers>

    if x in right_numbers:                # if searched number <x> is at right
        seen_times = right_numbers.count(x)     # how many times <x> is there?
        for times in range(seen_times):         # each time
            print(f'{numbers[i]}, {x}')         # print the number and <x>

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