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(){
    stack<int> S;
    string s;
    int a,b;
    while(cin>>s){
        if(s=="+"){a=S.top();S.pop();b=S.top();S.pop();S.push(a+b);}
        else if(s=="-"){a=S.top();S.pop();b=S.top();S.pop();S.push(b-a);}
        else if(s=="*"){a=S.top();S.pop();b=S.top();S.pop();S.push(a*b);}
        else S.push(atoi(s.c_str()));
    }
    printf("%d\n",S.top());
}
