#! perl -slw
use strict;

sub fib {
    my $n = shift;
    return 1 if $n == 1;
    return 1 if $n == 2;
    return fib( $n - 1 ) + fib( $n - 2 );
}

my $indent = -1;
sub fibx {
    ++$indent;
    my $n = shift;
    my $ret;
    if( $n == 1 ) {
        printf "%sfib( %d ) -> 1\n", '  .' x $indent, $n;
        $ret = 1;
    }
    elsif( $n == 2 ) {
        printf "%sfib( %d ) -> 1\n", '  .' x $indent, $n;
        $ret = 1;
    }
    else {
        printf "%sfib( %d ) ->fib( %d ) + fib( %d )\n", '  .' x $indent, $n, $n-1, $n-2;
        $ret = fibx( $n - 1 ) + fibx( $n - 2 );
    }
    --$indent;
    return $ret;
}

print fib( $ARGV[ 0 ] );
print fibx( $ARGV[ 0 ] );