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
#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<bits/stdc++.h>
using namespace std;

int istack[200]={}, l = 0;
void in(int a){istack[l++] = a;}
int out(void){return istack[--l];}

int main(){
  string a;
  while(cin>>a){
    if(a[0] == '+') in(out() + out());
    else if(a[0] == '-') {int a=out();int b=out();in(b-a);}
    else if(a[0] == '*') in(out() * out());
    else in(atoi(a.c_str()));
  }
  printf("%d\n",out());
  return 0;
}

