#!/usr/bin/env python3

import re
import sys
import subprocess

print(
    re.sub(
        r"^(```+)\$ (.*)\n((?:.+\n)*)\1$",
        lambda m: subprocess.check_output(
            m.group(2), input=m.group(3), shell=True, encoding="utf-8"
        ),
        sys.stdin.read(),
        flags=re.MULTILINE,
    )
)