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
from collections import deque

l = input().split()

st = deque()
for k in l:
    if k in "+*-":
        n2 = st.pop()
        n1 = st.pop()
        st.append(str(eval(n1 + k + n2)))
    else:
        st.append(k)

print(st[0])

