The iterated logarithm of n, written log* n (usually read "log star"), is the number of times the logarithm function must be iteratively applied before the result is less than or equal to 1.
In the question log*(log n) = log*n -1 if we are taking log then we are reducing the one count.
So in the result we have to subtract 1.
if the case is log*(log(log( n))) = log*n -2.
so by resoning we can prove this.