Consider the computational graph in the picture, where the inputs and outputs are all scalars. On the nodes of this graph, the operator $"$x$"$ denotes multiplication, $"+"$ is addition, $"+$a$"$ means incrementing the input by a$,"-$a$"$ means decrementing the input by a and ReLU is rectified linear unit. When computing the gradient of the output z with respect to w$1,$ find the downstream gradient v at the node $"+"($marked in green color$),$ for w$1=1\mathrm{.}0,$ w$2=2\mathrm{.}0,$ x$1=2\mathrm{.}0$ and x$2=0\mathrm{.}5.$ Type a single value into the box provided below.