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(){
	string s;
	int a, b;
	stack<int> st;
	while(cin >> s){
		if(s[0] == '+'){
			a = st.top();
			st.pop();
			b = st.top();
			st.pop();
			st.push(b + a);
		}else if(s[0] == '*'){
			a = st.top();
			st.pop();
			b = st.top();
			st.pop();
			st.push(b * a);
		}else if(s[0] == '-'){
			a = st.top();
			st.pop();
			b = st.top();
			st.pop();
			st.push(b - a);
		}else{
			st.push(atoi(s.c_str()));
		}
	}
	cout << st.top() << endl;
}