20250520

# arr=[]
# sum = 0
#
# for i in range(1,11) :
#     a,b=map(int,input().split())
#     sum = sum - a + b
#     arr.append(sum)
# print(max(arr))


#
# a,b,c=map(int,input().split())
# q=int(input())
#
# #h, m, s
#
# s = c+q
# m = b + s//60
# h = a + m//60
#
# print(h%24,m%60,s%60)
# n=int(input())
# w=0
# arr=input()
# list=[]
# for i in range(len(arr)-1,-1,-1) :
#     if w == 3:
#         list.append(',')
#         w = 0
#     w=w+1
#     list.append(arr[i])
# for i in range(len(list)-1,-1,-1) :
#     print(list[i],end='')

#
#
# k=int(input())
# stack = []
# for i in range(k) :
#     a=int(input())
#     if a!=0 :
#         stack.append(a)
#     else :
#         stack.pop()
#     # print(stack)
# print(sum(stack))