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 <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
#include<stack> 
using namespace std;



int main(){
  int x[200]={};int i=0;
  char str[20]={};
  while(cin >>str){
    if(str[0] =='+'){ x[i-1] +=x[i]; i--;}
    else if(str[0]=='-') {x[i-1] = x[i-1]-x[i]; i--;}
    else if(str[0]=='*') {x[i-1] *= x[i]; i--;}
    else{ i++; x[i] =atoi(str);}
    
  }
  cout <<x[1]<<"\n";
  return 0;
}


