Trivial sub-strings are { } and { GATE2013 } only..
No of sub-strings from n distinct character string
= n(n+1)/2 + 1 // n is no of characters in string, as we have 1 sub-strings of length n, 2 of length n-1, ... n sub-strings of length 1.
= 8*9/2 +1 = 36 + 1
= 37
Out of 35 total string, 2 are trivial so (37-2) 35 are non trivial..