input: def evaluate_postfix(expression: str) -> int:
      """Evaluate a postfix expression and return the result.
      >>> evaluate_postfix("2 3 + 4 5 * *")
      46
      >>> evaluate_postfix("5 3 * 2 +")
      17
      """
      tokens = expression.split()
      stack = []
      
      for token in tokens:
          if token.isdigit():
              stack.append(int(token))
          else:
              val1 = stack.pop()
              val2 = stack.pop()
              if token == '+':
                  stack.append(val2 + val1)
              elif token == '-':
                  stack.append(val2 - val1)
              elif token == '*':
                  stack.append(val2 * val1)
              elif token == '/':
                  stack.append(val2 // val1)  # Use integer division
                  
      return stack[0]
output:     tokens = expression.split()
      stack = []
      
      for token in tokens:
          if token.isdigit():
              stack.append(int(token))
          else:
              val1 = stack.pop()
              val2 = stack.pop()
              if token == '+':
                  stack.append(val2 + val1)
              elif token == '-':
                  stack.append(val2 - val1)
              elif token == '*':
                  stack.append(val2 * val1)
              elif token == '/':
                  stack.append(val2 // val1)  # Use integer division
                  
      return stack[0]