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 <cctype>
#include <algorithm>
using namespace std;

int main(void){
    stack<int> s;
    int a,b;
    string n;
    while(cin>>n){
        if(isdigit(n[0]))
            s.push(atoi(n.c_str()));
        else{
            a=s.top();
            s.pop();
            b=s.top();
            s.pop();
            if(n[0]=='+')b+=a;
            else if(n[0]=='-')b-=a;
            else if(n[0]=='*')b*=a;
            s.push(b);
        }
    }
    cout<<s.top()<<endl;
}