TechnoCup. First Round, C

Link to the problem

import sys

n = int(input())
c1 = 3 
c2 = 4
L = [0]*n

sys.stdout.write('? 1 2\n')
sys.stdout.flush()
sum12 = int(input())

sys.stdout.write('? 2 3\n')
sys.stdout.flush()
sum23 = int(input())

sys.stdout.write('? 1 3\n')
sys.stdout.flush()
sum13 = int(input())

L[0] = (sum13 + sum12 - sum23) // 2
L[1] = sum12 - L[0]
L[2] = sum13 - L[0]

if n == 3:
    print('!', *L)
else:
    n1 = 3
    while n1 < n:
        b = '? ' + str(c1) + ' ' + str(c2) + '\n'
        sys.stdout.write(b)
        sys.stdout.flush()
        sum34 = int(input())        
        L[n1] = sum34 - L[n1 - 1]
        n1 += 1
        c1 += 1
        c2 += 1
if n > 3:
    print('!', *L)