enum M{M;System z;int h,w,g,v,i,b;{try{for(;(b=z.in.read()%48)>0;)h-=b>9?w=h:-h*9-b;for(i=~w*h;i++<0;z.out.write(i%~w<0?b:10))for(g=h,v=w,b=97;g<v?i%~w>~(v-=g):i/~w<(g-=v);)b++;}catch(Exception e){}}}