IF Then Formula needed with Check Boxes

Hi,

I have created a performance evaluation form with checkboxes that should populat a value in the "Score" column if only 1 of the boxes in the preceeding 5 columns are checked. The result will show a number between 1-5, which aligns with our scoring system. This is the formula I have but I am having trouble getting it to work.

var A = this.getField("CheckBox1").value

var B = this.getField("CheckBox2").value

var C = this.getField("CheckBox3").value

var D = this.getField("CheckBox4").value

var E = this.getField("CheckBox5").value;

if(A=="CheckBox1") event.value=1;

else if(B=="CheckBox2") event.value=2;

else if(C=="CheckBox3") event.value=3;

else if(D=="CheckBox4") event.value=4;

else if(E=="CheckBox5") event.value=5;

else event.value=0;

See attached screenshot on what the end result should look like. I am looking for an "IF THEN" formula that will show this result.

Thank you so much for your help!