let P=3, Q=11. Accordingly n=33 and Z=20. Then:
We pick e=3 since gcd(3,20)=1
We solve 3d= 1 mod 20 to find d=7
To encrypt "YES" one would:
list the numeric values of YES: 25, 5, 19
encrypt 25 to 25^{3} mod 33 = 16
encrypt 5 to 5^{3} mod 33 = 26
encrypt 19 to 19^{3} mod 33 = 28
translate the sequence: 16,26,28 to "PZ+" which is the ciphertext.
To decrypt "PZ+" one would reverse 16^{7}=25, 26^{7}=5, 28^{7}=19, map the sequence 25,5,19 to "YES".

