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> st;
    string x;
    while(cin>>x)
    {
	if(x=="+" || x=="-" || x=="*")
        {
	    int a = st.top(); st.pop();
	    int b = st.top(); st.pop();
            if(x=="+") { st.push(b + a); }
	    if(x=="-") { st.push(b - a);  }
	    if(x=="*") { st.push(b * a);  }
        }
        else { st.push(stoi(x)); }
    }
	cout<<st.top()<<endl;
    return 0;
}

