Notes

Template in C

Constraints

2 ≤ the number of operands in the expression ≤ 100
1 ≤ the number of operators in the expression ≤ 99
-1 × 109 ≤ values in the stack ≤ 109

Input

An expression is given in a line. Two consequtive symbols (operand or operator) are separated by a space character.

You can assume that +, - and * are given as the operator and an operand is a positive integer less than 106

Output

Print the computational result in a line.

Examples

Input

1 2 +


Output

3


Input

1 2 + 3 4 - *


Output

-3
A = input().split()
G = []
j = 0
G.append(int(A[0]))

for i in range(1, len(A)):
	if A[i] == "+":
		G[j-1] += G[j]
		G.pop()
		j -= 1
	elif A[i] == "-":
		G[j-1] -= G[j]
		G.pop()
		j -= 1
	elif A[i] == "*":
		G[j-1] *= G[j]
		G.pop()
		j -= 1
	else:
		j += 1
		G.append(int(A[i]))

print(G[0])
		