include graph;
 size(15cm);
 real su=1.5;
 for(int k=0;k<4;++k){
 draw(circle((4k,su),1),black+linewidth(1.3pt));
 draw(circle((4k,-su),1),black+linewidth(1.3pt));
 label("$"+string(k+2)+"$",(4k,su),fontsize(30pt));
 label("$"+string(k+6)+"$",(4k,-su),fontsize(30pt));
 if(k!=0){
     draw((4(k-1)+cos(pi/6),su+sin(pi/6))..(4k-2,su+0.9)..(4k-cos(pi/6),su+sin(pi/6)),black+linewidth(1.3pt));
     label("$a_1$",(4k-2,su+0.4),fontsize(15pt));
     draw((4(k-1)+cos(pi/6),-su-sin(pi/6))..(4k-2,-su-0.9)..(4k-cos(pi/6),-su-sin(pi/6)),black+linewidth(1.3pt));
     label("$a_2$",(4k-2,-su-0.4),fontsize(15pt));
 }
 }
 filldraw(circle((-3.2,0),1),green,black+linewidth(1.3pt));
 filldraw(circle((15.2,0),1),red,black+linewidth(1.3pt));
 label("$1$",(-3.2,0),fontsize(30pt));
 label("$10$",(15.2,0),fontsize(30pt));
 draw((-3.2+cos(pi/3),sin(pi/3))..(-2,su)..(-cos(pi/9),sin(pi/9)+su),black+linewidth(1.3pt));
 draw((-3.2+cos(pi/3),-sin(pi/3))..(-2,-su)..(-cos(pi/9),-sin(pi/9)-su),black+linewidth(1.3pt));
 draw((12+cos(pi/9),su+sin(pi/9))..(14,su)..(15.2-cos(pi/3),sin(pi/3)),black+linewidth(1.3pt));
 draw((12+cos(pi/9),-su-sin(pi/9))..(14,-su)..(15.2-cos(pi/3),-sin(pi/3)),black+linewidth(1.3pt));
 label("$a_1$",(-1.7,1.15),fontsize(15pt));
 label("$a_2$",(-1.7,-1.15),fontsize(15pt));
 label("$a_1$",(13.7,1.15),fontsize(15pt));
 label("$a_2$",(13.7,-1.15),fontsize(15pt));