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;
#define MAX 100010

int main(){
  stack<int>A;
  int a,b;
  char c[20];
  while(cin>>c){
    if(c[0]=='+'){
      b=A.top();A.pop();
      a=A.top();A.pop();
      A.push(a+b);
    }
    else if(c[0]=='-'){
      b=A.top();A.pop();
      a=A.top();A.pop();
      A.push(a-b);
    }
    else if(c[0]=='*'){
      b=A.top();A.pop();
      a=A.top();A.pop();
      A.push(a*b);
    }
    else{
      A.push(atoi(c));
    }
  }
  printf("%d\n",A.top());
}
