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 <string.h>
#include <stdlib.h>
int top,S[1000];
void push(int x){
  S[++top]=x;
}
int pop(void){
  top--;
  return S[top+1];
}
int main(){
  int a,b;
  char ch[1000];
  top=0;
  while(scanf("%s",ch)!=EOF){
    if(ch[0]=='+'){
      a=pop();
      b=pop();
      push(a+b);
    } else if(ch[0]=='-'){
      b=pop();
      a=pop();
      push(a-b);
    } else if(ch[0]=='*'){
      a=pop();
      b=pop();
      push(a*b);
    } else {
      push(atoi(ch));
    }
  }
  printf("%d\n",pop());
  return 0;
}