void Solve(StreamScanner ss, StreamWriter sw)
{
//---------------------------------
var N = ss.Next(Int);
var A1 = ss.Next(Int, N);
var A2 = ss.Next(Int, N);
var max = 0;
for (var i = 0; i < N; i++)
{
max = Math.Max(max, A1.Take(i + 1).Sum() + A2.Skip(i).Sum());
}
sw.WriteLine(max);
//---------------------------------
}