#!/usr/bin/env python
import re, sys

if len(sys.argv) < 2: sys.exit(1)

def read_file (file, chunk_size=65536):
    """
    Lazy function generator to read a file in chunks,
    including to the end of line.
    """
    while True:
        chunk = file.read(chunk_size)
        if not chunk:
            break
        if not chunk.endswith('\n'):
            chunk += file.readline()
        yield chunk

mul_re = re.compile(r"mul\(\d{1,3},\d{1,3}\)")
filename = sys.argv[1]
count = 0

try:
    with open (filename, "r") as file:
        for chunk in read_file(file):
            count += len(mul_re.findall(chunk))
except Exception as e:
    print(e, file=sys.stderr)
    sys.exit(1)

print(f"Found {count} matches.")