Dude.. I am not math major in any way.. but I was interested so I tried after going through some site  (wiki and others)

I found
[ //regentsprep.org/Regents/Math/tables/ifthen.htm ]
Enrichment only: (not tested on Math A or Math B)
Mathematicians often use symbols and tables to represent concepts in logic.  The use of these variables, symbols and tables creates a shorthand method for discussing logical sentences.
Truth table for conditional (if...then):
(notice the symbol used for "if...then" in the table below)
          
T    T    T
T    F    F
F    T    T
F    F    T
    A truth table is a pictorial representation of all of the possible outcomes of the truth value of a compound sentence.  Letters such as  and  are used to represent the facts (or sentences) within the compound sentence.
 


((P→Q)→R)→S)



So According to it


P    Q    P->Q
T    T    T
T    F    F
F    T    T
F    F    T
 
Now trying each (P->Q) for different R

P->Q    R    ((P-Q)->R)
T    T    T
F    T    T
T    T    T
T    T    T
T    F    F
F    F    T
T    F    F
T    F    F
 
((P-Q)->R)    S    (((P-Q)->R)->S)
T    T    T
T    T    T
T    T    T
T    T    T
F    T    T
T    T    T
F    T    T
F    T    T
T    F    F
T    F    F
T    F    F
T    F    F
F    F    T
T    F    F
F    F    T
F    F    T

I also think that it is correct. As 4 variables can have 2^4=16 states, the final table have same number