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() {
  char buf[256];
  stack<int> stk;
  while(scanf("%s", buf) != EOF) {
    if(isdigit(buf[0])) {
      stk.push(atoi(buf));
    } else {
      int b = stk.top(); stk.pop();
      int a = stk.top(); stk.pop();
      switch(buf[0]) {
      case '+': stk.push(a+b); break;
      case '-': stk.push(a-b); break;
      case '*': stk.push(a*b); break;
      }
    }
  }
  printf("%d\n", stk.top());
  return 0;
}

