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>
using namespace std;
int main(){
	string s; stack<int> sta; int a, b;
	while(cin >> s){
			if (s == "+") { a = sta.top(); sta.pop(); b = sta.top(); sta.pop(); sta.push(a + b);}
			else if (s == "*") { a = sta.top(); sta.pop(); b = sta.top(); sta.pop(); sta.push(b * a);}
			else if (s == "-") { a = sta.top(); sta.pop(); b = sta.top(); sta.pop(); sta.push(b - a);}
			else sta.push(stoi(s));
	}
	printf("%d\n", sta.top());
}
