What is the meaning of d1 ,d2 in the running result of ResPRE?

Merry Christmas!
I run ResPRE service on the ZhangLab website. Here are the results returned. But I don't understand what is the meaning of d1, d2?
Thank you!
PFRMAT RR
TARGET
AUTHOR ResPRE
REMARK The full prediction can be viewed at https://zhanglab.ccmb.med.umich.edu/ResPRE/output/RPC136
METHOD contact prediction by deep residual neural networks
MODEL 1
EDPEVLFKNKGCVACHAIDTKMVGPAYKDVAAKFAGQAGAEAELAQRIKN
GSQGVWGPIPMPPNAVSDDEAQTLAKWVLSQK
i j d1 d2 p
3 74 0 8 0.9964910000
3 77 0 8 0.9961920000
6 74 0 8 0.9949530000
44 75 0 8 0.9915450000
3 73 0 8 0.9878440000
.....