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
//By Vlgd
#include<bits/stdc++.h>
using namespace std;
int top=0,S[1000];
void push(int x){S[++top]=x;}
int pop(){return S[top--];}
int main(){
	char s[100];
	int a,b;
	while(scanf("%s",s)!=EOF){
		if (s[0]=='+'){
			a=pop();b=pop();
			push(a+b);
		}
		else if (s[0]=='-'){
			a=pop();b=pop();
			push(b-a);
		} 
		else if	(s[0]=='*'){
			a=pop();b=pop();
			push(a*b);
		}
		else push(atoi(s));
	}
	printf("%d\n",pop());
} 
