#include <cstring>
#include <cstdio>
struct node
{
    char a[2005];
    int b[2005];
    int len;
    void reverse()
    {
        for(int i=0;i<len;++i) b[len-i+1]=a[i]-‘0‘;
    }
    bool operator - (node m)const
    {
        for(int i=1;i<=len;++i)
        {
            
 
if(b[i]<0) b[i+1]=b[i+1]-b[i],b[i]=b[i]+(-b[i]);
            for(;b[i]<m.b[i];b[i]++,b[i+1]--);
            b[i]=b[i]-m.b[i];
        }
    }
    bool operator<(node m)const
    {
        if(len!=m.len) return len>m.len;
        else 
        {
            for(int i=0;i<len;++i) if
 
(a[i]!=m.a[i]) return a[i]>m.a[i];
        }
    }
}aa,bb,cc;
int main()
{
    scanf("%s%s",aa.a,bb.a);
    aa.len=strlen(aa.a);
    bb.len=strlen(bb.a);
    aa.reverse();
    bb.reverse();
    if(aa.a>bb.a) aa-bb;
    else 
    {
        puts("-");
        bb-aa;
    }
    puts(cc.a);
    
 
return 0;
}

未完成代碼