NG
This is the consonant "i-ung". It has approximately the same sound as English "ng" in "spring". It is written as a single circular stroke written in a counter-clockwise direction. Note that this letter is also written at the beginning of syllables beginning with a vowel sound as a place-holder. Thus, it is pronounced as "ng" at the end of a syllable and not pronounced at all at the beginning of a syllable.