function [ y ] = exams_1_2015(n,AM)
if round(n)~=n||n<0
    disp([num2str(n),' is not an integer'])
	y=NaN;
	return
end
if n<2
    y=11;
else 
    y=exams_1_2015(n-1,AM)+AM*n^(1/n);
end
end


