Count cells equal to case sensitive

The EXACT function takes two arguments, text1 and text2. When text1 and text2 match exactly (respecting case), EXACT returns TRUE. Otherwise, EXACT returns FALSE:

=EXACT("ayako","ayako") // returns TRUE
=EXACT("ayako","Ayako") // returns FALSE

In the example shown, we need check all values in column B each time we count a name in column D. Because we are giving EXACT multiple values, it returns multiple results. In E5, EXACT returns:

{FALSE;FALSE;FALSE;FALSE;TRUE;TRUE;TRUE}

Each TRUE represents an exact match of "ayako" in B5:B11. Because we want to count results, we use a double-negative (--) to convert TRUE and FALSE values into 1's and 0's. The resulting array is:

{0;0;0;0;1;1;1}

Finally, SUMPRODUCT sums the values in the array and returns 3.

Note: Because SUMPRODUCT can handle arrays natively, it's not necessary to use Control+Shift+Enter to enter this formula.