digraph G {
N1 -> N2
N1 -> N6
N4 -> N5
N2 -> N3
N2 -> N4
N7 -> N5
N6 -> N7
N6 -> N4
N1 [ label="/",  shape="parallelogram"]
N3 [ label="a[i]",  shape="box"]
N5 [ label="a",  shape="box"]
N4 [ label="min",  shape="ellipse"]
N2 [ label="-",  shape="parallelogram"]
N7 [ label="max",  shape="ellipse"]
N6 [ label="-",  shape="parallelogram"]
}