How Many D's Are There?

Create a function that counts how many D's are in a sentence.

Examples

countDs("My friend Dylan got distracted in school.") ➞ 4

countDs("Debris was scattered all over the yard.") ➞ 3

countDs("The rodents hibernated in their den.") ➞ 3

Notes

• Your function must be case-insensitive.
• Remember to return the result.
• Check the Resources for help.