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 st[200];
char in[1000010];

int main(){
  int sp = 0;
  while( cin >> in ){
    if( '0' <= in[0] && in[0] <= '9' ){
      st[sp++] = atoi( in );
    }else{
      int a = st[--sp];
      int b = st[--sp];
      if( in[0] == '+' ){
	st[sp++] = b + a;
      }else if( in[0] == '-' ){
	st[sp++] = b - a;
      }else{
	st[sp++] = b * a;
      }
    }
  }

  assert( sp == 1 );
  cout << st[sp - 1] << endl;
}

