My program get WA #4. Give me some tests, please.
This is main part of my solution:

    L := 0;
    read(S.y,S.x);
    for i := 1 to k do begin
        read(F.y,F.x);
        cL := BFS(S,F);
        if cL=-1 then
            Continue;
        S := F;
        L := L+cL;
    end;
    L := L/V;
    write(L:0:2);