The input contains a single integer *a* (1 ≤ *a* ≤ 64).

Output a single integer.
The input contains a single integer *a* (1 ≤ *a* ≤ 64).
a = input()
if len(a) == 1:
    print(int(a) // 2)
else:
    if a[0] > a[1]:
        print(int(a[0]) + int(a[1]))
    else:
        print(int(a[1]) - int(a[0]))
