Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| --- | --- | --- | --- | --- |
| ㅏ | U+314F | U+1161 | U+F807 | U+FFC2 |
| ᅶ | — | U+1176 | U+F808 | — |
| ᅷ | — | U+1177 | U+F809 | — |
| ㅏㅡ | — | U+11A3 | U+F80A | — |
| ㅐ | U+3150 | U+1162 | U+F80B | U+FFC3 |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㅑ | U+3151 | U+1163 | U+F80C | U+FFC4 |
| ᅸ | — | U+1178 | U+F80D | — |
| ᅹ | — | U+1179 | U+F80E | — |
| ㅑㅜ | — | U+11A4 | U+F80F | — |
| ㅒ | U+3152 | U+1164 | U+F810 | U+FFC5 |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㅓ | U+3153 | U+1165 | U+F811 | U+FFC6 |
| ᅺ | — | U+117A | U+F812 | — |
| ᅻ | — | U+117B | U+F813 | — |
| ᅼ | — | U+117C | U+F814 | — |
| ㅔ | U+3154 | U+1166 | U+F815 | U+FFC7 |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㅕ | U+3155 | U+1167 | U+F816 | U+FFCA |
| ㅕㅑ | — | U+11A5 | U+F817 | — |
| ᅽ | — | U+117D | U+F818 | — |
| ᅾ | — | U+117E | U+F819 | — |
| ㅖ | U+3156 | U+1168 | U+F81A | U+FFCB |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㅗ | U+3157 | U+1169 | U+F81B | U+FFCC |
| ㅘ | U+3158 | U+116A | U+F81C | U+FFCD |
| ㅙ | U+3159 | U+116B | U+F81D | U+FFCE |
| ㅗㅑ | — | U+11A6 | U+F81E | — |
| ㅗㅒ | — | U+11A7 | U+F81F | — |
| ᅿ | — | U+117F | U+F820 | — |
| ᆀ | — | U+1180 | U+F821 | — |
| ㅗㅕ | — | U+D7B0 | U+F822 | — |
| ᆁ | — | U+1181 | U+F823 | — |
| ᆂ | — | U+1182 | U+F824 | — |
| ㅗㅗㅣ | — | U+D7B1 | U+F825 | — |
| ᆃ | — | U+1183 | U+F826 | — |
| ㅚ | U+315A | U+116C | U+F827 | U+FFCF |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㅛ | U+315B | U+116D | U+F828 | U+FFD2 |
| ㅛㅏ | — | U+D7B2 | U+F829 | — |
| ㅛㅐ | — | U+D7B3 | U+F82A | — |
| ㆇ | U+3187 | U+1184 | U+F82B | — |
| ㆈ | U+3188 | U+1185 | U+F82C | — |
| ㅛㅓ | — | U+D7B4 | U+F82D | — |
| ᆆ | — | U+1186 | U+F82E | — |
| ᆇ | — | U+1187 | U+F82F | — |
| ㆉ | U+3189 | U+1188 | U+F830 | — |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㅜ | U+315C | U+116E | U+F831 | U+FFD3 |
| ᆉ | — | U+1189 | U+F832 | — |
| ᆊ | — | U+118A | U+F833 | — |
| ㅝ | U+315D | U+116F | U+F834 | U+FFD4 |
| ᆋ | — | U+118B | U+F835 | — |
| ㅞ | U+315E | U+1170 | U+F836 | U+FFD5 |
| ㅜㅕ | — | U+D7B5 | U+F837 | — |
| ᆌ | — | U+118C | U+F838 | — |
| ᆍ | — | U+118D | U+F839 | — |
| ㅟ | U+315F | U+1171 | U+F83A | U+FFD6 |
| ㅜㅣㅣ | — | U+D7B6 | U+F83B | — |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㅠ | U+3160 | U+1172 | U+F83C | U+FFD7 |
| ᆎ | — | U+118E | U+F83D | — |
| ㅠㅐ | — | U+D7B7 | U+F83E | — |
| ᆏ | — | U+118F | U+F83F | — |
| ᆐ | — | U+1190 | U+F840 | — |
| ㆊ | U+318A | U+1191 | U+F841 | — |
| ㆋ | U+318B | U+1192 | U+F842 | — |
| ㅠㅗ | — | U+D7B8 | U+F843 | — |
| ᆓ | — | U+1193 | U+F844 | — |
| ㆌ | U+318C | U+1194 | U+F845 | — |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㅡ | U+3161 | U+1173 | U+F846 | U+FFDA |
| ㅡㅏ | — | U+D7B9 | U+F847 | — |
| ㅡㅓ | — | U+D7BA | U+F848 | — |
| ㅡㅔ | — | U+D7BB | U+F849 | — |
| ㅡㅗ | — | U+D7BC | U+F84A | — |
| ᆕ | — | U+1195 | U+F84B | — |
| ᆖ | — | U+1196 | U+F84C | — |
| ㅢ | U+3162 | U+1174 | U+F84D | U+FFDB |
| ᆗ | — | U+1197 | U+F84E | — |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㅣ | U+3163 | U+1175 | U+F84F | U+FFDC |
| ᆘ | — | U+1198 | U+F850 | — |
| ᆙ | — | U+1199 | U+F851 | — |
| ㅣㅑㅗ | — | U+D7BD | U+F852 | — |
| ㅣㅒ | — | U+D7BE | U+F853 | — |
| ㅣㅕ | — | U+D7BF | U+F854 | — |
| ㅣㅖ | — | U+D7C0 | U+F855 | — |
| ᆚ | — | U+119A | U+F856 | — |
| ㅣㅗㅣ | — | U+D7C1 | U+F857 | — |
| ㅣㅛ | — | U+D7C2 | U+F858 | — |
| ᆛ | — | U+119B | U+F859 | — |
| ㅣㅠ | — | U+D7C3 | U+F85A | — |
| ᆜ | — | U+119C | U+F85B | — |
| ㅣㅣ | — | U+D7C4 | U+F85C | — |
| ᆝ | — | U+119D | U+F85D | — |
| Jamo | Hangul Compatibility | Hangul Jamo Area | Hanyang Private Use | Halfwidth |
| ㆍ | U+318D | U+119E | U+F85E | — |
| ㆍㅏ | — | U+D7C5 | U+F85F | — |
| ᆟ | — | U+119F | U+F860 | — |
| ㆍㅔ | — | U+D7C6 | U+F861 | — |
| ᆠ | — | U+11A0 | U+F862 | — |
| ㆎ | U+318E | U+11A1 | U+F863 | — |
| ᆢ | — | U+11A2 | U+F864 | — |
Question:
what is the number of halfwidth are there?
Answer:
21