text: #  Created by Egor Kostan.
  #  GitHub: https://github.com/ikostan
  #  LinkedIn: https://www.linkedin.com/in/egor-kostan/
  
  
  def calculate(s: str) -> str:
      CONVERSION = {
          'plus': '+',
          'minus': '-',
      }
  
      s = s.lower()
      for key in CONVERSION:
          if key in s:
              s = s.replace(key, CONVERSION[key])
  
      return str(eval(s))
  