take_skip_rope

input_string = list(input())

numbers = [int(n) for n in input_string if n.isdigit()]
none_numbers = [s for s in input_string if not s.isdigit()]
take_list = [n for i, n in enumerate(numbers) if i % 2 == 0]
skip_list = [n for i, n in enumerate(numbers) if i % 2 != 0]

taken = []
skipped = []

for i in range(len(take_list)):
    index_taken = take_list[i]
    taken = taken + none_numbers[:index_taken]
    index_skipped = skip_list[i]
    skipped = none_numbers[index_taken:index_taken + index_skipped]
    none_numbers = none_numbers[index_skipped + index_taken:]
print("".join(taken))