20250506

# arr= input()
# d=input()
#
# for i in range(0,len(d)) :
#     if d[i]!=' ' :
#         print(arr.index(d[i]),end='')
#
#     else :
#         print(' ',end='')
#
# # for i in range(0,len(d)) :
#     for j in range(0,10) :
#         if d[i]==arr[j] :
#             print(j,end='')
#         elif d[i]==' ' :
#             print(' ',end='')



arr=input()
b = []


for i in range(0,len(arr)) :
    if arr[i]=='A' :
        if len(b)!=0 :
            b.pop()
    elif arr[i]=='B' :
        if len(b) != 0:
            b.pop()
            b.pop()
    elif arr[i]=='c' :
        for j in range(0,len(b)) :
            b.pop()
    else :
        b.append
print(b)