Gets and sets the property InputKey.
The name of the .png or .jpg file that you want to use for the watermark. To determine
which Amazon S3 bucket contains the specified file, Elastic Transcoder
checks the pipeline specified by 
CopyC#; the Pipeline
CopyC# object in that pipeline identifies the bucket.
Input
Bucket
If the file name includes a prefix, for example, logos/128x64.png, include the prefix in the key. If the file isn't in the specified bucket, Elastic Transcoder returns an error.
Declaration Syntax| C# |
public string InputKey { get; set; }