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<cmath>
#include<string>
#include<cstdlib>
using namespace std;


int main(){
	int st[500];
	int p = 0;
	for(;;){
		string s;
		if(!(cin >> s)) break;
		char op = s.at(0);
		int num;

		if(op>='0' && op<='9'){
			num = atoi(s.c_str());
			st[p] = num;
			p++;
		}else{
			if(op=='+') st[p-2] = st[p-2]+st[p-1];
			if(op=='-') st[p-2] = st[p-2]-st[p-1];
			if(op=='*') st[p-2] = st[p-2]*st[p-1];
			p--;
		}
	}
	cout << st[p-1] << endl;
	return 0;
}