Stack

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

inputFormat

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

outputFormat

Output

Print the computational result in a line.

Examples

Input

1 2 +

Output

3

Input

1 2 + 3 4 - *

Output

-3

样例

1 2 + 3 4 - *

-3