function y=ADBD(K11,K12,K2,n,M1,M2,M3)
%K11	possibility of reaction between PR-AD and PR-AD
%K12	possibility for a PR-AD to bind a PR-BD
%K2		possibility for a dimer to decompose
for i=1:n
	for j=1:(i+1)
		p11(i,j)=K11*(2*(M1*(j-1)+M2*(i-(j-1)))/(M1*((j-1)+1)+M2*(i-(j-1))))^(-1/2)*((M1^(1/3)+(M1*(j-1)+M2*(i-(j-1)))^(1/3))/(2*M1^(1/3)))^2;
		p12(i,j)=K12*((M1+M2)*(M1*(j-1)+M2*(i-(j-1)))/(M1*(M1*((j-1))+M2*(i-(j-1)+1))))^(-1/2)*((M2^(1/3)+(M1*(j-1)+M2*(i-(j-1)))^(1/3))/(M2^(1/3)+M1^(1/3)))^2;
	end
	p2(i)=K2*i/2;
end
a(row(n,n),row(n,n))=0;
b(row(n,n))=0;
if n>2
	for i=1:n
		for j=0:i
			if i==1&&j==1
				a(row(i,j),row(1,1))=p12(1,1+1)+p11(1,1+1);
				a(row(i,j),row(i+1,j))=-p2(i+1)*(i+1-j)/(i+1);
				a(row(i,j),row(i+1,j+1))=-p2(i+1)*(j+1)/(i+1);
			end
			if i==n&&j==0
				a(row(i,j),row(n,0))=p2(n);
				a(row(i,j),row(n-1,0))=-p12(n-1,0+1);
			end
			if i==n&&j==n
				a(row(i,j),row(n,n))=p2(n);
				a(row(i,j),row(n-1,n-1))=-p11(n-1,(n-1)+1);
			end
			if i==n&&j~=0&&j~=n
				a(row(i,j),row(n,j))=p2(n);
				a(row(i,j),row(n-1,j))=-p12(n-1,j+1);
				a(row(i,j),row(n-1,j-1))=-p11(n-1,(j-1)+1);
			end
			if i==j&&i~=1&&i~=n
				a(row(i,j),row(i,i))=p2(i)+p11(i,i+1)+p12(i,i+1);
				a(row(i,j),row(i+1,i))=-p2(i+1)/(i+1);
				a(row(i,j),row(i+1,i+1))=-p2(i+1);
				a(row(i,j),row(i-1,i-1))=-p11(i-1,(i-1)+1);
			end
			if i~=1&&i~=n&&j==0
				a(row(i,j),row(i,0))=p11(i,0+1)+p12(i,0+1)+p2(i);
				a(row(i,j),row(i+1,1))=-p2(i+1)/(i+1);
				a(row(i,j),row(i+1,0))=-p2(i+1);
				if i==2
					b(row(i,j))=p12(i-1,0+1);
				else 
					a(row(i,j),row(i-1,0))=-p12(i-1,0+1);
				end
			end
			if i~=1&&i~=n&&j~=0&&j~=i
				a(row(i,j),row(i,j))=p11(i,j+1)+p12(i,j+1)+p2(i);
				if i==2&&j==1
					b(row(i,j))=p11(i-1,(j-1)+1);
				else
					a(row(i,j),row(i-1,j-1))=-p11(i-1,(j-1)+1);
				end
				a(row(i,j),row(i+1,j+1))=-p2(i+1)*(j+1)/(i+1);
				a(row(i,j),row(i+1,j))=-p2(i+1)*(i+1-j)/(i+1);
				a(row(i,j),row(i-1,j))=-p12(i-1,j+1);
			end
		end
	end
else 
	if n==2
		a(1,1)=p12(1,1+1)+p11(1,1+1);
		a(1,3)=-p2(2)/2;
		a(1,4)=-p2(2);
		a(2,2)=p2(2);
		a(3,1)=-p12(1,1+1);
		a(3,3)=p2(2);
		a(4,1)=-p11(1,1+1);
		a(4,4)=p2(2);
		b(2)=p12(1,0+1);
		b(3)=p11(1,0+1);
	end
end
			
c=b/a';

m1=M1-M3;
m2=M2-M3;
N1=(8*m1/(0.7405*M3))^2;
N2=(8*m2/(0.7405*M3))^2;

s1=1;
s2=0;
for i=1:n
	for j=0:i
		s1=s1+i*c(row(i,j));
		if i<min(N1,N2)&&j~=0&&j~=i&&i>1
			s2=s2+c(row(i,j));
		end
	end
end
y=2*s2/s1;
%y=p11(1,0+1)/p12(1,1+1)-c(row(1,1));
%p11(1,0+1)/p12(1,1+1)-c(row(1,1))
%c