pubkey1         = 13135480;
pubkey2         = 8821721;
loopsize        = 0;
subjectNumber   = 7;
val             = 7;
while val~=pubkey1
    loopsize    = loopsize + 1;
    val         = val * subjectNumber;
    val         = rem(val,20201227);
end
subjectNumber   = pubkey2;
val             = pubkey2;
for i=1:loopsize
    val         = val * subjectNumber;
    val         = rem(val,20201227);
end
disp(val)