with open('input20.txt','r') as f:
    inp = f.read().splitlines(keepends=False)

sequence = []

for i in range(len(inp)):
    if int(inp[i]) == 0:
        zero = (i, int(inp[i]))
    sequence.append((i, int(inp[i])))
numbers = sequence.copy()

for number in sequence:
    if sequence.count(number) > 1:
        print('!')

for number in numbers:
    #print(number[0])
    index = sequence.index(number)
    _number = number[1]
    newIndex = index + _number
    while not (len(sequence) * -1) <= newIndex < len(sequence):
        if newIndex < (len(sequence) * -1):
            newIndex += len(sequence)
        if newIndex >= len(sequence):
            newIndex -= len(sequence) - 1
    if newIndex == 0:
        newIndex = len(sequence) - 1
    elif newIndex < 0:
        newIndex = len(sequence) -1 + newIndex
    if _number >= len(sequence):
        newIndex += 1
    if _number <= (len(sequence)* -1):
        newIndex -= 1
    if newIndex > index:
        newIndex += 1
        sequence.insert(newIndex, number)
        sequence.pop(index)
    else:
        sequence.pop(index)
        sequence.insert(newIndex, number)
    #print(sequence)


number = sequence.index(zero) + 1000
_sum = 0
for i in range(3):
    number %= len(sequence)
    #print(sequence[number])
    _sum += sequence[number][1]
    number += 1000

print(_sum)