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 <cmath>
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm>
using namespace std;
int s[105],p=0;
char in[10];
int main()
{
    while(cin>>in)
        if(in[0]=='+')s[p]+=s[p--];
        else if(in[0]=='-')s[p]-=s[p--];
        else if(in[0]=='*')s[p]*=s[p--];
        else s[++p]=atoi(in);
    cout<<s[1]<<endl;
    return 0;
}
