C is the 3rd button of the 1st row ?
You could withdraw 1 on the tabs... But there is another solution :
Count the keys beginning with the top of your accordion considering that the 1st key is the key n°2 (and count: 2,3,4…)
C is the 2nd button of the 1st row ?
Consider that your key n°1 is in fact the key n°3 (and count: 3,4,5…)