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>
#include<cstdio>
#include<cstdlib>

using namespace std;

int top, s[1000];

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

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

int main(){
	int b, a;
	top = 0;
	char c[3];
	while(cin >> c){
		if(c[0] == '+'){
			a = pop();
			b = pop();
			push(a+b);
		}
		else if(c[0]=='-'){
			a = pop();
			b = pop();
			push(b - a);
		}
		else if(c[0]=='*'){
			a = pop();
			b = pop();
			push(a * b);
		}
		else{
			push(atoi(c));
		}
	}
	cout << pop() << endl;
	return 0;
}

