高精度减法

var

n1,n2,temp:string;

a,b,c:array[1..256] of integer;

lena,lenb,lenc,i,j:integer;

begin

fillchar(a,20,0);

fillchar(b,20,0);

fillchar(c,20,0);

readln(n1);

lena:=length(n1);

readln(n2);

lenb:=length(n2);

if (lena