cf push error when omitting app name

cf-cli-output.txt

$ cf push -m 64M
FAILED
Manifest file is not found in the current directory, please provide either an app name or manifest

NAME:
   push - Push a new app or sync changes to an existing app

USAGE:
   Push a single app (with or without a manifest):
   cf push APP_NAME [-b BUILDPACK_NAME] [-c COMMAND] [-d DOMAIN] [-f MANIFEST_PATH] [--docker-image DOCKER_IMAGE]
   [-i NUM_INSTANCES] [-k DISK] [-m MEMORY] [--hostname HOST] [-p PATH] [-s STACK] [-t TIMEOUT] [-u HEALTH_CHECK_TYPE] [--route-path ROUTE_PATH]
   [--no-hostname] [--no-manifest] [--no-route] [--no-start]

   Push multiple apps with a manifest:
   cf push [-f MANIFEST_PATH]


ALIAS:
   p

OPTIONS:
   -b                           Custom buildpack by name (e.g. my-buildpack) or Git URL (e.g. 'https://github.com/cloudfoundry/java-buildpack.git') or Git URL with a branch or tag (e.g. 'https://github.com/cloudfoundry/java-buildpack.git#v3.3.0' for 'v3.3.0' tag). To use built-in buildpacks only, specify 'default' or 'null'
   -c                           Startup command, set to null to reset to default start command
   -d                           Domain (e.g. example.com)
   --docker-image, -o           Docker-image to be used (e.g. user/docker-image-name)
   -f                           Path to manifest
   --health-check-type, -u      Application health check type (e.g. 'port' or 'none')
   --hostname, -n               Hostname (e.g. my-subdomain)
   -i                           Number of instances
   -k                           Disk limit (e.g. 256M, 1024M, 1G)
   -m                           Memory limit (e.g. 256M, 1024M, 1G)
   --no-hostname                Map the root domain to this app
   --no-manifest                Ignore manifest file
   --no-route                   Do not map a route to this app and remove routes from previous pushes of this app
   --no-start                   Do not start an app after pushing
   -p                           Path to app directory or to a zip file of the contents of the app directory
   --random-route               Create a random route for this app
   --route-path                 Path for the route
   -s                           Stack to use (a stack is a pre-built file system, including an operating system, that can run apps)
   -t                           Maximum time (in seconds) for CLI to wait for application start, other server side timeouts may apply