with open("input/day13.txt") as f:
    input = f.read()

scanners = {}

for line in input.splitlines():
    parts = line.split(": ")
    d, r = int(parts[0]), int(parts[1])

    assert d not in scanners, "no overlapping scanners"
    scanners[d] = r


def part1(scanners):
    severity = 0
    for d in range(max(scanners.keys()) + 1):
        r = scanners.get(d)
        if r is None:
            continue

        assert r > 1, r
        cycle = (r - 1) * 2
        pos = d % cycle
        if pos == 0:
            severity += d * r
    return severity


print(part1(scanners))