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 <cstdio>
#include <cstdlib>
#include <stack>

using namespace std;

int main()
{
  char s[100];
  stack<int> st;
  
  while (scanf("%s", s) != EOF)
    if (s[0] == '+') {
       int temp = st.top();
       st.pop();
       st.top() += temp;
    } else if (s[0] == '-') {
       int temp = st.top();
       st.pop();
       st.top() -= temp;
    } else if (s[0] == '*') {
       int temp = st.top();
       st.pop();
       st.top() *= temp;
    } else
      st.push(atoi(s));
  
  printf("%d\n", st.top());
}
