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<stdio.h>
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cmath>
#include<vector>
using namespace std;
int top,S[1000];

void push(int x){
 S[++top]=x;
}

int pop(){
 top--;
 return S[top+1];
}

int main(){
int v;
char n[100];
while (scanf("%s", n) != EOF){
  if (n[0] == '+'){
   push(pop() + pop());
  }else if (n[0] == '-'){
    int b=pop();
    int a=pop();
   push(a-b);
  }else if (n[0] == '*'){
   push(pop() * pop());
  }else {
   push(atoi(n));
  }
}
  printf("%d\n",pop());
  return 0;
}