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<cstdio>
#include<cstdlib>
#include<iostream>
using namespace std;

int top,S[101];

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

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

int main(){
	char str[10];
	int a,b;
	top = 0;
	
	while(scanf("%s",str) != EOF){
		if(str[0]=='+'){
			a=pop();
			b=pop();
			push(a+b);
		}else if(str[0]=='-'){
			a=pop();
			b=pop();
			push(b-a);
		}else if(str[0]=='*'){
			a=pop();
			b=pop();
			push(a*b);
		}else{
			push(atoi(str));
		}
	}
	cout<<pop()<<endl;
}