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 <stack>
#include <string>
#include <stdlib.h>
using namespace std;
int main(){
    stack<int> D;
    string S;
    while (cin>>S){
		if (S == "+"|| S=="-" || S=="*"){
			int b = D.top();
            D.pop();
            int a = D.top();
            D.pop();
            if (S=="+"){
			    D.push(b+a);
			}
			if (S=="-"){
				D.push(a-b);
			}
			if (S == "*"){
				D.push(a*b);
			}
		}
		else{
			D.push(atoi(S.c_str()));
		}
	}

	cout << D.top() << endl;

	return 0;
}
