People in the Tomskaya region like magic formulas very much. You can see some of them below.

Imagine you are given a sequence of positive integer numbers *p*<sub class="lower-index">1</sub>, *p*<sub class="lower-index">2</sub>, ..., *p*<sub class="lower-index">*n*</sub>. Lets write down some magic formulas:

Here, "mod" means the operation of taking the residue after dividing.

The expression <img align="middle" class="tex-formula" src="https://espresso.codeforces.com/b364f2e04c665b78b924ec10666327a4ef4635bc.png" style="max-width: 100.0%;max-height: 100.0%;"/> means applying the bitwise *xor* (excluding "OR") operation to integers *x* and *y*. The given operation exists in all modern programming languages. For example, in languages C++ and Java it is represented by "^", in Pascal — by "xor".

People in the Tomskaya region like magic formulas very much, but they don't like to calculate them! Therefore you are given the sequence *p*, calculate the value of *Q*.
The first line of the input contains the only integer *n* (1 ≤ *n* ≤ 10<sup class="upper-index">6</sup>). The next line contains *n* integers: *p*<sub class="lower-index">1</sub>, *p*<sub class="lower-index">2</sub>, ..., *p*<sub class="lower-index">*n*</sub> (0 ≤ *p*<sub class="lower-index">*i*</sub> ≤ 2·10<sup class="upper-index">9</sup>).
from sys import stdin
def main():
    inp=stdin
    n=int(inp.readline().strip())
    pi=inp.readline().strip().split()
    ppi=[]
    u=0
    while u < n:
        ppi.append(magic(int(pi[u]),n,u+1))
        u+=1
    q=ppi[0]
    p=1
    while p < n:
        q=q^ppi[p]
        p+=1
    print(q)

def magic(pi,n,i):
    rep=0
    y=1
    qi=pi^(i % y)
    while y <= n:
        rep=qi ^ (i % y)
        qi= rep
        y+=1
    return rep
main()    
