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<stdio.h>
#include<stdlib.h>

int top = 0;
int stack[100];

void push(int x) {
  top++;
  stack[top-1] = x;
}

int pop() {
  top--;
  return stack[top];
}

int main() {
  char s[7];
  int a, b;

  while ( scanf("%s", s) != EOF ) {
    if ( s[0] == '+' ) {
      push(pop() + pop());
    } else if ( s[0] == '-' ) {
      b = pop();
      a = pop();
      push(a - b);
    } else if ( s[0] == '*' ) {
      push(pop() * pop());
    } else {
      push(atoi(s));
    }
  }

  printf("%d\n", pop());

  return 0;
}

