function [basin,h]=depth(fai0,c,y0,lay,n)
if n==lay
    h=y0;
    basin=h(n);
    return;
end
h(1)=0;
t=0;
for i=2:n
    h(i)=base(fai0,c,t,y0(lay-n+i-1),y0(lay-n+i));
    t=h(i);
end

basin=h(n);
end