1. An alphabet input system, comprising: a plurality of representative keys that is used to input first matched characters among alphabets; and combination keys that are input by combining any one of the plurality of representative keys and are used to generate combination characters which are alphabets except for the first characters, wherein the combination characters are pictographically derived from combinations of a combination symbol having a ‘reversed J’ shape as the combination key with a shape of the first character matching to each of the plurality of representative keys (here, the reversed J means a reversed shape of J).