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(void) {
    stack<int> st;
    string s;
    while(cin >> s) {
        if(s == "+" || s == "-" || s == "*") {
            int a = st.top();
            st.pop();
            int b = st.top();
            st.pop();
            if(s == "+") st.push(b + a);
            if(s == "*") st.push(b * a);
            if(s == "-") st.push(b - a);
        }
        else {
            st.push(atoi(s.c_str()));
        }
    }
    cout << st.top() << endl;
}
