Problems
C0n + ... + Cnn
C0n + ... + Cnn
Given a non-negative integer $n$, find the sum of binomial coefficients:
$$
C_n^{0} + C_n^{1} + ... + C_n^{n}
$$
\InputFile
One non-negative integer $n~(n \le 60)$.
\OutputFile
Print the value of the sum.
Input example #1
2
Output example #1
4