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

Stack=[]
def push(x):
    Stack.append(x)

def pop():
    return Stack.pop()

def solve():
    s_list=raw_input().split()
    for i in range(len(s_list)):
        if s_list[i]=='+':
            b=pop()
            a=pop()
            push(a+b)
        elif s_list[i]=='-':
            b=pop()
            a=pop()
            push(a-b)
        elif s_list[i]=='*':
            b=pop()
            a=pop()
            push(a*b)
        else:
            push(int(s_list[i]))
    print(pop())

def main():
    if __name__=="__main__":
        solve()

main()