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>
#define prinf printf

int main(){
  char a[10];
  int stack[100];
  int head=0;

  while(scanf("%s",a)!=EOF){
    if(a[0]=='+'){
      stack[head-2]=stack[head-2]+stack[head-1];
      head--;
    }else if(a[0]=='-'){
      stack[head-2]=stack[head-2]-stack[head-1];
      head--;
    }else if(a[0]=='*'){
      stack[head-2]=stack[head-2]*stack[head-1];
      head--;
    }else{
      stack[head]=atoi(a);
      head++;
    }
  }
  
  prinf("%d\n",stack[0]);
  
  return 0;
}
  