Update app.py

app.py

@@ -40,13 +40,14 @@ def convert_to_french_letters(number):
             words.append('cent')
         else:
             words.append(units[hundreds] + ' cent')
+            
     if tens_and_units > 0:
         if tens_and_units < 10:
             words.append(units[tens_and_units])
         elif tens_and_units < 20:
             words.append('dix-' + units[tens_and_units-10])
         else:
-            tens_digit = tens[tens_and_units // 10]
+            tens_digit = tens[int(tens_and_units / 10)]
             units_digit = units[tens_and_units % 10]
             if tens_digit == 'vingt' and units_digit == 'un':
                 tens_digit = 'vingt-et-un'