Sereja and Arcs

Sereja have N points, with coordinates (1, 0), (2, 0), ..., (N, 0). Every point has a color, point with coordinate (i, 0) has color A[i]. Sereja have painted arcs between every pair of points with same color. Formally Sereja painted arc between points (i, 0) and (j, 0) if A[i] = A[j] and i != j, such arc has color A[i]. All the arcs are painted such way that they will reside along the positive qu