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<iostream>
using namespace std;

int stack[1000];
int top=-1;

void push(int v){
	top++;
	stack[top]=v;
}

int pop(){
	if (top < 0){
		return -1;
	}
	top--;
	return stack[top+1];
}

int main(){
	
	string str;
	while (cin >> str){
		if (str == "+"){
			push(pop()+pop());
		}else if(str == "*"){
			push(pop()*pop());
		}else if(str == "-"){
			int n1=pop();
			int n2=pop();
			push(n2-n1);
		}else{
			push(atoi(str.c_str()));
		}
	}
	cout << pop() << endl;
	return 0;
}


