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 <bits/stdc++.h>
using namespace std;

int main(void){
	stack<int> st;
	string s;
	while(cin >> s){
		char c = s[0];
		if(isdigit(c)){
			st.push(stoi(s));
		}else{
			int b = st.top();st.pop();
			int a = st.top();st.pop();
			int ret = 0;
			if(c == '+') ret = a + b;
			else if(c == '-') ret = a - b;
			else if(c == '*') ret = a * b;
			st.push(ret);
		}
		cin.ignore();
	}	
	cout << st.top() << endl;
	return 0;
}