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 <cstdlib>
using namespace std;

int main() {
	stack<int> st;
	char s[10];
	int a=0,b=0;
	while(cin>>s){
		if(s[0]=='+'){
			a = st.top(); st.pop();
			b = st.top(); st.pop();
			st.push(a+b);
		}
		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(a*b);
		}
		else{
			st.push(atoi(s));
		} 
	}
	cout << st.top() << endl;
	return 0;
}
