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>
using namespace std;

int main() 
{ 
    int a1, a2;
    char c[3];
    stack<int> s;
    while(cin >> c)
    {
        if (isdigit(c[0]))
        {
            s.push(atoi(c));
        }
        else
        {
            a1 = s.top(); s.pop();
            a2 = s.top(); s.pop();
            if (c[0]=='+') s.push(a2+a1);
            else if (c[0]=='-') s.push(a2-a1);
            else if (c[0]=='*') s.push(a2*a1);
        }
    }
    printf("%d\n", s.top());
}
