import sys

framebefore = int(sys.argv[1])
total = int(sys.argv[2]) if len(sys.argv) == 4 else framebefore+10
filename = sys.argv[-1]

convert = [i for i in range(total)]

with open(filename) as decimate:
    decimateframes = []
    for line in decimate:
        dec = int(line.strip()[:-2])
        if dec > total:
            break
        decimateframes.append(dec)
current = 0
sub = 0

# insert decimated frames according to cycle of 5, if not in dec file
for cycle in range(0,total,5):
    cycledecimated = False
    for cycleframe in range(cycle,cycle+5):
        if cycleframe in decimateframes:
            cycledecimated = True
            break
    if not cycledecimated:
        decimateframes.append(cycle)

decimateframes.sort()

for currentdec in decimateframes:
    while current-1 != currentdec and current < total:
        convert[current] -= sub
        current += 1

    if current + 1 < total:
        sub += 1

        convert[current] -= sub if current > 0 else 0
        current += 1

print("Frame before decimation:",framebefore)
print("Frame after decimation:",convert[framebefore])