input = "blah-blah\nublR+iVp4k0KLTdJt7jULC0uIrZY3UkJuYZ56859aK+Ftc1H4ja5ei+0a2s49M2BIt+CSBnuQc0V\n6tLIrxTsdiZ//9k=\nblah-blah"
puts input.match /^(?:[A-Za-z0-9+\/]{4}\n?)*(?:[A-Za-z0-9+\/]{2}==|[A-Za-z0-9+\/]{3}=)?$/
aW5wdXQgPSAiYmxhaC1ibGFoXG51YmxSK2lWcDRrMEtMVGRKdDdqVUxDMHVJclpZM1VrSnVZWjU2ODU5YUsrRnRjMUg0amE1ZWkrMGEyczQ5TTJCSXQrQ1NCbnVRYzBWXG42dExJcnhUc2RpWi8vOWs9XG5ibGFoLWJsYWgiCnB1dHMgaW5wdXQubWF0Y2ggL14oPzpbQS1aYS16MC05K1wvXXs0fVxuPykqKD86W0EtWmEtejAtOStcL117Mn09PXxbQS1aYS16MC05K1wvXXszfT0pPyQv