What is the output of this Java program?

$```$

class Driver $\{$

public static void main$($String$[]$ args$)\{$

int a $=90$;

for $($int i $=6$; i $>1$; i$--)\{$

a $=$ a $-$ i;

$\}$

System.out.print$($a$)$;

$\}$

$\}$

$```$