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;

stack<int> S;
int a, b, x;
string s;

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

