ffmpeg - skipping frames while watermarking

I am building a video watermark utility based on ffmpeg.

But watermarking takes considerable time. I wish to reduce the watermarking time by skipping frames while processsing.

Is it possible to skip frames while processing video?

Like adding text to only every other frame?

ffmpeg  -i "D://sample.mp4"  -vf [in]drawtext=fontfile='C\://Windows//Fonts//Calibri.ttf':fontsize=27.9:text=www.example.com:fontcolor=#ffffff:box=1:boxcolor=0x00000099:x=w-tw-10:y=h-th-10 -y D:\watermarked.mp4