#!/usr/bin/python2.3

import sys

def doThrow(dice, sum=0):
  for throw in [throw.split('d') for throw in dice.split('+')]:
    if len(throw) == 1 and throw[0].isdigit():
      sum += int(throw[0])
    elif len(throw) == 2 and throw[0].isdigit() and throw[1].isdigit():
      sum += int(throw[0]) * int(throw[1])
  return sum

if __name__ == '__main__':
  print doThrow(''.join(sys.argv[1:]))