Positive:
L		expected result: L only
L+		expected result: L+ only
L+4		expected result: +++ Valid
L+34		expected result: +++ Valid
L+4467		expected result: +++ Valid
L24		expected result: Valid
L34553		expected result: Valid

Negative:
LL		expected result: Invalid
L0		expected result: Invalid
L+0		expected result: Invalid
L+l		expected result: Invalid
L+35l		expected result: Invalid
L23l		expected result: Invalid