240818

# # a = []

# #

#b = [0 for i in range(10)]

# #

# # print(b)

# #

# # b.append(10) #

# #

# # b.insert(2,5)

# #

# # print(b)

# #

# # b.pop() #

# #

# # del b[1]

# #

# # b.remove(5)

# #

# # b.append(4)

# #

# # print(b)

# #

# # print(len(b)) #

# # print(sum(b))

# # print(max(b))

# # print(min(b))

# #

# # b.reverse()

# #

# # print('count',b.count(4))

# #

# print('index',b.index(79))

# #

# # print(b)

# #

# #

# # print(b[2:4])

# #

#print(b[-1])

# #

# # print(b[3:-1])

#

# # a = []

# # k = int(input())

# # for i in range(k):

# # n = int(input())

# # a.append(n)

# # c = 0

# # b = a.count(0)

# # for i in range(b):

# # c = a.index(0)

# # del a[c]

# # del a[c-1]

# #

# # print(sum(a))

#

# k = int(input())

# n = input()

# a = k // 3

# b = k / 3

# x = list(n)

# x.reverse()

# if a == b:

# for i in range(1, a):

# x.insert(4 * i - 1, ',')

# else:

# for i in range(1, a+1):

# x.insert(4*i-1, ',')

#

# x.reverse()

# for i in range(len(x)):

# print(x[i], end='')

# x = []

# # k = int(input())

# # for i in range(k):

# # a = input()

# # if a == 'top()':

# # if len(x) == 0:

# # print('-1')

# # else:

# # print(x[-1])

# #

# # elif a == 'pop()':

# # if len(x) != 0:

# # x.pop()

# # elif a == 'size()':

# # print(len(x))

# # elif a == 'empty()':

# # if len(x) == 0:

# # print('true')

# # else:

# # print('false')

# #

# # else:

# # xarr = a.split(' ')

# # x.append(xarr[1])

a = input().split()

x = []

for i in range(len(a)):

if a[i] != '*' and a[i] != '-' and a[i] != '+' and a[i] != ' ':

x.append(int(a[i]))

else:

if a[i] != ' ':

p = x.pop()

q = x.pop()

if a[i] == '*':

x.append(p*q)

elif a[i] == '-':

x.append(q-p)

else:

x.append(p+q)

print(x[-1])