5133 by rr

(5+1)*(3-3)=0
f((5+1)*(3-3))=1
s(5-1)+3-3=2
s(5-1)+3/3=3
5-1+3-3=4
5*1+3-3=5
5+1+3-3=6
5+1+3/3=7
-s(5-1)+3/.3=8
5+1+s(3*3)=9
s(f(5)+1)-3/3=10
s(f(5)+1)+3-3=11
s(f(5)+1)+3/3=12
5*s(1+3)+3=13
5-1+3/.3=14
5*1+3/.3=15
5+1+3/.3=16
s(f(5)+1)+3+3=17
(5+1)*s(3*3)=18
-5+f(1+s(3*3))=19
s(5-1)*3/.3=20