P10818 [EC Final 2020] Random Shuffle

Prof. Pang is selecting teams that advance to the world final contest. As the regionals are cancelled, he uses random shuffle to rank the teams. There are $n$ teams in total. His code is as follows: ```cpp uint64_t x;//uint64_t represents 64-bit unsigned integer int n; uint64_t rand() {//this is a xor-shift random generator x ^= x > 7; x ^= x > n; cin >> x; for (int i = 1; i

The first line contains a single integer $n$ ($50\le n\le 100000$) -- the number of teams. The next line contains $n$ integers -- the result printed by Prof. Pang's code. It is guaranteed that the result is correct, i.e., there exists an integer $x$ ($0\le x\le 2^{64}-1$) that leads to the result.

Output the integer $x$ ($0\le x\le 2^{64}-1$) Prof. Pang had entered. If there are multiple possible $x$'s, print any one.

Note that the second line of the sample input is wrapped to fit in the width of page.