8
min(a[1],a[2])
min(min(a[1],a[2]),a[3])
min(a[1],min(a[2],a[3]))
min(min(min(a[1],a[2]),a[3]),a[4])
min(min(a[1],min(a[2],a[3])),a[4])
min(min(a[1],a[2]),min(a[3],a[4]))
min(a[1],min(min(a[2],a[3]),a[4]))
min(a[1],min(a[2],min(a[3],a[4])))