import re

pattern = re.compile(r'validation_0')

with open('output.log', 'r') as input_file, open('output_filted.log', 'w') as output_file:
    for line in input_file:
        if "validation_0" not in line:
            output_file.write(line)
        else:
            if "99" in line[:5]:
                output_file.write(line)