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;


// グローバル変数
int A[100];
int top;

void initialize() {
  top = 0;
}

int pop() {
  top--;
  return A[top+1];
}

void push(int s) {
  top++;
  A[top] = s;
}


int main() {
  char s;
  initialize();
  while (scanf("%s", &s) != EOF) {
    if (s == '+' || s == '-' || s == '*') {
      int b = pop();
      int a = pop();
      if (s=='+') push(a+b);
      else if (s=='-') push(a-b);
      else if (s=='*') push(a*b);
    } else push(atoi(&s));
  }
  printf("%d\n", pop());
}
