Language: C++

#!/usr/bin/env python3

'''
Author: andyli
Time: 2020-07-05 19:56:22
'''

import os
from io import BytesIO, IOBase
import sys


def main():
    n = int(input())
    ans = n*(n+1)*(n+2) // 6
    for i in range(n-1):
        u,v = map(int,input().split())
        if u > v:
            u,v = v,u
        ans -= u*(n-v+1)
    print(ans)
    return


# region fastio
BUFSIZE = 1048576


class FastIO(IOBase):
    newlines = 0

    def __init__(self, file):
        self._fd = file.fileno()
        self.buffer = BytesIO()
        self.writable = 'x' in file.mode or 'r' not in file.mode
        self.write = self.buffer.write if self.writable else None

    def read(self):
        while True:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            if not b:
                break
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines = 0
        return self.buffer.read()

    def readline(self):
        while self.newlines == 0:
            b = os.read(self._fd, max(os.fstat(self._fd).st_size, BUFSIZE))
            self.newlines = b.count(b'\n') + (not b)
            ptr = self.buffer.tell()
            self.buffer.seek(0, 2), self.buffer.write(b), self.buffer.seek(ptr)
        self.newlines -= 1
        return self.buffer.readline()

    def flush(self):
        if self.writable:
            os.write(self._fd, self.buffer.getvalue())
            self.buffer.truncate(0), self.buffer.seek(0)


class IOWrapper(IOBase):
    def __init__(self, file):
        self.buffer = FastIO(file)
        self.flush = self.buffer.flush
        self.writable = self.buffer.writable
        self.write = lambda s: self.buffer.write(s.encode('ascii'))
        self.read = lambda: self.buffer.read().decode('ascii')
        self.readline = lambda: self.buffer.readline().decode('ascii')


sys.stdin, sys.stdout = IOWrapper(sys.stdin), IOWrapper(sys.stdout)
def input(): return sys.stdin.readline().rstrip('\r\n')

# endregion


if __name__ == '__main__':
    main()


Compiler output:
a.cc:1:2: error: invalid preprocessing directive #!
    1 | #!/usr/bin/env python3
      |  ^
a.cc:3:1: error: empty character constant
    3 | '''
      | ^~
a.cc:3:3: warning: missing terminating ' character
    3 | '''
      |   ^
a.cc:3:3: error: missing terminating ' character
a.cc:6:1: error: empty character constant
    6 | '''
      | ^~
a.cc:6:3: warning: missing terminating ' character
    6 | '''
      |   ^
a.cc:6:3: error: missing terminating ' character
a.cc:25:3: error: invalid preprocessing directive #region
   25 | # region fastio
      |   ^~~~~~
a.cc:68:59: warning: multi-character literal with 5 characters exceeds 'int' size of 4 bytes
   68 |         self.write = lambda s: self.buffer.write(s.encode('ascii'))
      |                                                           ^~~~~~~
a.cc:69:55: warning: multi-character literal with 5 characters exceeds 'int' size of 4 bytes
   69 |         self.read = lambda: self.buffer.read().decode('ascii')
      |                                                       ^~~~~~~
a.cc:70:63: warning: multi-character literal with 5 characters exceeds 'int' size of 4 bytes
   70 |         self.readline = lambda: self.buffer.readline().decode('ascii')
      |                                                               ^~~~~~~
a.cc:74:49: warning: multi-character character constant [-Wmultichar]
   74 | def input(): return sys.stdin.readline().rstrip('\r\n')
      |                                                 ^~~~~~
a.cc:76:3: error: invalid preprocessing directive #endregion
   76 | # endregion
      |   ^~~~~~~~~
a.cc:79:16: warning: multi-character literal with 8 characters exceeds 'int' size of 4 bytes
   79 | if __name__ == '__main__':
      |                ^~~~~~~~~~
a.cc:3:1: error: expected unqualified-id before '\x0'
    3 | '''
      | ^~