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<string.h>
#include<stdlib.h>
using namespace std;
int top,s[1000];

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

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

int main(){
int a,b;
top=0;
char s[100];
while(scanf("%s",s)!=-1){
if(s[0]=='+'){
    a=pop();
    b=pop();
    push(a+b);
}
else if(s[0]=='-'){
    b=pop();
    a=pop();
    push(a-b);
}
else if(s[0]=='*'){
    a=pop();
    b=pop();
    push(a*b);
}
else {push(atoi(s));}
}
printf("%d\n",pop());
return 0;
}