import fileinput

input = fileinput.input()

arrival = int(next(input))
buses = [None if bus == "x" else int(bus) for bus in next(input).split(",")]
print(arrival, buses)

remainders = [-(arrival % (-bus)) if bus else float("inf") for bus in buses]
print(remainders)

print(
    "Part 1:",
    min(enumerate(buses), key=lambda x: remainders[x[0]])[1] * min(remainders),
)

def combine(a_period, a_offset, b_period, b_offset):
    gcd, s, _ = egcd(a_period, b_period)
    diff = a_offset - b_offset
    diff_quot, dif_rem = divmod(diff, gcd)
    assert(dif_rem == 0)

    combined_period = a_period // gcd * b_period
    combined_offset = (a_offset - s * diff_quot * a_period) % combined_period
    return combined_period, combined_offset

def egcd(a, b):
    r_, r = a, b
    s_, s = 1, 0
    t_, t = 0, 1
    while r:
        quot, rem = divmod(r_, r)
        r_, r = r, rem
        s_, s = s, (s_ - quot * s)
        t_, t = t, (t_ - quot * t)
    return r_, s_, t_

period = 1
offset = 0

for i, bus in enumerate(buses):
    if bus is None:
        continue

    period, offset = combine(period, offset, bus, i)
    print(i, bus, period, offset)

print(-offset % period)