add solution for TaskC21

TaskC21_TODO/solution.py

@@ -0,0 +1,25 @@
+# HORSE HEAD -> 46773 4323
+import re
+import sys
+
+pattern = r'^[A-Z][A-Z][A-Z][A-Z][A-Z] [A-Z][A-Z][A-Z][A-Z]$'
+
+def get_number(c):
+   result = re.sub(r'[ABC]', '2', c)
+   result = re.sub(r'[DEF]', '3', result)
+   result = re.sub(r'[GHI]', '4', result)
+   result = re.sub(r'[JKL]', '5', result)
+   result = re.sub(r'[MNO]', '6', result)
+   result = re.sub(r'[PQRS]', '7', result)
+   result = re.sub(r'[TUV]', '8', result)
+   result = re.sub(r'[WXYZ]', '9', result)
+   return result
+
+for line in sys.stdin:
+   line = line.strip()
+   if not re.match(pattern, line):
+       print('no')
+       continue
+       
+   num = ''.join(get_number(c) for c in line.replace(' ', ''))
+   print('yes' if re.match(r'^467734323$', num) else 'no')