diff --git a/Lib/tokenize.py b/Lib/tokenize.py
index f8ac40116c9bd7..0ab1893d42f72f 100644
--- a/Lib/tokenize.py
+++ b/Lib/tokenize.py
@@ -215,8 +215,9 @@ def untokenize(self, iterable):
             elif tok_type == FSTRING_MIDDLE:
                 if '{' in token or '}' in token:
                     end_line, end_col = end
-                    token = re.sub(r'(?<!\\N){([^{}]*)}', r'{{\1}}', token)
-                    end = (end_line, end_col + token.count('{') + token.count('}') - 2)
+                    end = (end_line, end_col + token.count('{') + token.count('}'))
+                    token = re.sub('{', '{{', token)
+                    token = re.sub('}', '}}', token)
 
 
             self.add_whitespace(start)
@@ -263,7 +264,8 @@ def compat(self, token, iterable):
                 startline = False
             elif toknum == FSTRING_MIDDLE:
                 if '{' in tokval or '}' in tokval:
-                    tokval = re.sub(r'(?<!\\N){([^{}]*)}', r'{{\1}}', tokval)
+                    tokval = re.sub('{', '{{', tokval)
+                    tokval = re.sub('}', '}}', tokval)
 
             toks_append(tokval)
 
diff --git a/lol.py b/lol.py
new file mode 100644
index 00000000000000..9d1d64baa646ab
--- /dev/null
+++ b/lol.py
@@ -0,0 +1 @@
+compile('match y:\n case e(e=v,v,', '<na>', 'exec')