function [n]=tilgung(K)         %
global K R TZ p0 p1 p2 Z A
n=1;              %Monate
while K>0 
  if n==1
    K=(K-R)*(1+p0)^(1/12);
    Z=K*p0/12;
    elseif n<=12*TZ    
      K(n)=(K(n-1)-R)*(1+p0)^(1/12);
      Z(n)=K(n)*p0/12;
    elseif n>12*TZ && n<12*2*TZ
      K(n)=(K(n-1)-R)*(1+p1)^(1/12);
      Z(n)=K(n)*p1/12;
    elseif n>=12*2*TZ
      K(n)=(K(n-1)-R)*(1+p2)^(1/12);
      Z(n)=K(n)*p2/12;
  endif
  n=n+1;
  if n>12*(100-A)
     break
  endif
endwhile
endfunction