Walk through the following code that counts how many adjacent duplicates are in a sequence of non$-$negative integer inputs, using

a negative value as the sentinel$.$ Assume the inputs are $1,2,2,4,4,-1$

duplicates $=0$

value $=$ int$($input$("$Enter a value: $"))$

while value $>=0$ :

previous $=$ value

value $=$ int$($input$("$Enter a value: $"))$

if value $==$ previous :

duplicates $=$ duplicates $+1$

print$($duplicates$)$