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 <cstdio>
#include <cstring>
#include <cstdlib>

int top,S[1000];

void push(int x){
  S[++top]=x;
}

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

int main(){
  int a,b;
  char s[100];
  top=0;
  while(scanf("%s",s)!=EOF){
    if(s[0]=='+'){
      b=pop();
      a=pop();
      push(a+b);
    }
    else if(s[0]=='-'){
      b=pop();
      a=pop();
      push(a-b);
    }
    else if(s[0]=='*'){
      b=pop();
      a=pop();
      push(a*b);
    }
    else{
      push(atoi(s));
    }
    }
  printf("%d\n",pop());
  return 0;
  }