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<bits/stdc++.h>
using namespace std;
int top,s[101];
void push(int x){
  s[++top]=x;
}
int pop(){
  --top;
  return s[top+1];
}
int main(){
  int a,b;
  char c[101];
  while(cin>>c){
    if(c[0]=='+'){
      a=pop();
      b=pop();
      push(b+a);
    }else if(c[0]=='-'){
      a=pop();
      b=pop();
      push(b-a);
    }else if(c[0]=='*'){
      a=pop();
      b=pop();
      push(b*a);
    }else{
      push(atoi(c));
    }
  }
  cout<<pop()<<endl;
  return 0;
}