output_description: If a+b=15, print `+`; if a\times b=15, print `*`; if neither holds, print `x`.
  
  * * *
input_description: Input is given from Standard Input in the following format:
  
      
      
      a b
attempt: import itertools
  from collections import deque, defaultdict, Counter
  from itertools import accumulate
  import bisect
  from heapq import heappop, heappush, heapify
  from fractions import gcd
  from copy import deepcopy
  import math
  import queue
  import numpy as np
  
  # import sympy as syp(素因数分解とか)
  Mod = 1000000007
  import sys
  
  sys.setrecursionlimit(100000)
  
  
  def sieve_of_eratosthenes(n):
      if not isinstance(n, int):
          raise TypeError("n is not int")
      if n < 2:
          raise ValueError("n is not effective")
      prime = [1] * (n + 1)
      for i in range(2, int(math.sqrt(n)) + 1):
          if prime[i] == 1:
              for j in range(2 * i, n + 1):
                  if j % i == 0:
                      prime[j] = 0
      res = []
      for i in range(2, n + 1):
          if prime[i] == 1:
              res.append(i)
      return res
  
  
  class UnionFind:
      def __init__(self, n):
          self.parent = [i for i in range(n + 1)]
          self.rank = [0 for i in range(n + 1)]
  
      def findroot(self, x):
          if x == self.parent[x]:
              return x
          else:
              y = self.parent[x]
              y = self.findroot(self.parent[x])
              return y
  
      def union(self, x, y):
          px = self.findroot(x)
          py = self.findroot(y)
          if px < py:
              self.parent[py] = px
          else:
              self.parent[px] = py
  
      def same_group_or_no(self, x, y):
          return self.findroot(x) == self.findroot(y)
  
  
  def main():  # startline-------------------------------------------
      a, b = map(int, input().split())
      if a + b == 15:
          print("+")
      elif a * b == 15:
          print("*")
      else:
          print("x")
  
  
  if __name__ == "__main__":
      main()  # endline===============================================
  
problem_description: Statement
  
  You are given two integers a and b. Determine if a+b=15 or a\times b=15 or
  neither holds.
  
  Note that a+b=15 and a\times b=15 do not hold at the same time.
samples: [{"input": "4 11", "output": "+\n    \n\n4+11=15.\n\n* * *"}, {"input": "3 5", "output": "*\n    \n\n3\\times 5=15.\n\n* * *"}, {"input": "1 1", "output": "x\n    \n\n1+1=2 and 1\\times 1=1, neither of which is 15."}]