function solve()
    n = readline() |> x->parse(Int, x)
    a = [readline() for _ in 1:n]
    s = Set()
    for i in 1:n
        for j in 1:n
            if i == j
                continue
            end
            push!(s, a[i]*a[j])
        end
    end
    println(length(s))
end
solve()