n = io.read("*n")
t = {}
for i = 1, n do
    a = io.read("*n")
    t[i] = a
end
table.sort(t)
min = 0
for i = 1, n - 1 do
    d = math.abs(t[i] - t[i + 1])
    if(0 < d and (d < min or min == 0)) then min = d end
end
print(min)