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(){
	int a, b;
	string s;
	vector<int> st;
	while(cin >> s) {
		if(s == "+") {
			a = st.back(); st.pop_back();
			b = st.back(); st.pop_back();
			st.push_back(a + b);
		}else if(s == "-") {
			a = st.back(); st.pop_back();
			b = st.back(); st.pop_back();
			st.push_back(b - a);
		}else if(s == "*") {
			a = st.back(); st.pop_back();
			b = st.back(); st.pop_back();
			st.push_back(a * b);
		}else{
			st.push_back(stoi(s));
		}
	}
	printf("%d\n", st.back());
}

