Relation between hop_length, win_length, frame_length, n_fft, no.of frames

I am working with mfcc features mfccs = librosa.feature.mfcc(y=y,sr=sr,n_mfcc=12,n_fft=320,hop_length=320,htk=True) Here ,i took audio signal of 1s duration which gave me len(y) as 16000 and i took sr as 16000 .I calculated no.of frames using n,n_f=mfccs.shape , where n is no.of mfcc coefficients(12) and n_f is no.of frames.I got n_f or no.of frames as 51. But i didn't understand how 51 is possible.What is the relation between no.of frames , hop_length, n_fft, win_length. No where i found relation. please explain.Thanks in advance I am coding in python