'''
@Author: your name
@Date: 2020-07-10 23:17:01
@LastEditTime: 2020-07-11 01:07:21
@LastEditors: Please set LastEditors
@Description: In User Settings Edit
@FilePath: \vscode_py\day5.py
'''
# Question16
# 计算奇数的平方
def Q16():
    r=[]
    l=input().split(',')
    for i in l:
        if int(i)%2!=0:
            r.append(str(int(i)**2))
    print(",".join(r))


# Question17
# 根据关键字来计算银行账户的余额
def Q17():
    money=0

    while True:
        l=input().split()
        print(l)
        if not l:
            break
        cm,num=map(str,l)
        
        if cm=="D":
            money+=int(num)
        if cm=='W':
            money-=int(num)
    
    print(money)


    # total = 0
    # while True:
    #     s = input().split()
    #     if not s:            # break if the string is empty
    #         break
    #     cm,num = map(str,s)    # two inputs are distributed in cm and num in string data type

    #     if cm=='D':
    #         total+=int(num)
    #     if cm=='W':
    #         total-=int(num)

    # print(total)




if __name__ == "__main__":
    # Q16()

    Q17()