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 <cstdlib>

using namespace std;

int main(){
    int i = 0;
    string n;
    int a[100];
    while(cin >> n){
        if(n=="+"){
            a[i-2] = a[i-1] + a[i-2];
            i--;
        }
        else if(n=="-"){
            a[i-2] = a[i-2] - a[i-1];
            i--;
        }
        else if(n=="*"){
            a[i-2] = a[i-2] * a[i-1];
            i--;
        }
        else{
            a[i] = atoi(n.c_str());
            i++;
        }
    }
    cout << a[0] << endl;
}
