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 main(){
  char op[1000200];
  int memory[100],cnt=0;
  while(scanf("%s",op)!=EOF){
    if(op[0]=='+'){
      memory[cnt-2]+=memory[cnt-1];
      cnt--;
    }else if(op[0]=='-'){
      memory[cnt-2]-=memory[cnt-1];
      cnt--;
    }else if(op[0]=='*'){
      memory[cnt-2]*=memory[cnt-1];
      cnt--;
    }else{
      memory[cnt]=atoi(op);
      cnt++;
    }
  }
  printf("%d\n",memory[0]);
}