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
l = input().split()
m = []
for i in range(len(l)):
    if l[i] == "+":
        m[-2] += m[-1]
        m.pop()
    elif l[i] == "-":
        m[-2] -= m[-1]
        m.pop()
    elif l[i] == "*":
        m[-2] *= m[-1]
        m.pop()
    else:
        m.append(int(l[i]))
print(m[0])
