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 <string>

using namespace std;
int main(void){

    int l,r;
    string in;
    stack<int> s;

    while(cin >> in){
        if(in=="+" or in=="-" or in=="*"){
            r = s.top();
            s.pop();
            l = s.top();
            s.pop();
            if(in=="+") s.push(l+r);
            if(in=="-") s.push(l-r);
            if(in=="*") s.push(l*r);
        }else{
            s.push(std::stoi(in));
        }
    }
    
    cout << s.top() << endl;
}
