#include <iostream>
#include <cstring>
#include <string>
#include <cstdio>
using namespace std;
//500 digits at most
struct Num{
int num[1000],len;
Num(){
memset(num,0,sizeof(num));
len=1;
}
Num(const string &s){
len=s.size();
memset(num,0,sizeof(num));
for(int i=0;i<len;++i){
num[i]=s[len-1-i]-‘0’;
}
}
Num& operator=(const Num& right){
copy(right.num,right.num+right.len,this->num);
len=right.len;
return *this;
}
friend ostream& operator<<(ostream &os,const Num &output){
for(int i=output.len-1;i>=0;–i)
os<<output.num[i];
return os;
}
friend Num operator+(Num &x,Num &y){
Num ans;
ans.len=max(x.len,y.len);
for(int i=0;i<ans.len;++i){
ans.num[i]=x.num[i]+y.num[i];
}
for(int i=0;i<ans.len;++i){
ans.num[i+1]+=ans.num[i]/10;
ans.num[i]%=10;
}
if(ans.num[ans.len]) ++ans.len;
return ans;
}
friend Num operator-(const Num &left,const Num& right){
Num ans;
ans.len=max(left.len,right.len);
for(int i=0;i<ans.len;++i)
ans.num[i]=left.num[i]-right.num[i];
for(int i=0;i<ans.len;++i){
if(ans.num[i]<0){
–ans.num[i+1];
ans.num[i]+=10;
}
}
while(ans.len>1 && !ans.num[ans.len-1]) –ans.len;
return ans;
}
friend Num mul_digit(int x,Num y){
Num ans=y;
for(int i=0;i<ans.len;++i){
ans.num[i]*=x;
}
for(int i=0;i<ans.len;++i){
ans.num[i+1]+=ans.num[i]/10;
ans.num[i]%=10;
}
if(ans.num[ans.len]) ++ans.len;
return ans;
}
friend Num mul(const Num &x,const Num &y){
if(x.len==1 || y.len==1){
if(x.len==1) return mul_digit(x.num[0],y);
else return mul_digit(y.num[0],x);
}
Num a,b,c,d,ans;
int len1=x.len>>1,len2=y.len>>1;
// cout<<“len “<<len1<<” “<<len2<<endl;
copy(x.num,x.num+x.len-len1,b.num);
b.len=x.len-len1;
copy(x.num+x.len-len1,x.num+x.len,a.num);
a.len=len1;
copy(y.num,y.num+y.len-len2,d.num);
d.len=y.len-len2;
copy(y.num+y.len-len2,y.num+y.len,c.num);
c.len=len2;
Num tem_ac=mul(a,c),tem_bd=mul(b,d),ac,bd,fin_cdab;
Num cdab;
if(x.len-len1>=y.len-len2){
Num aa,new_ac;
copy(a.num,a.num+a.len,aa.num+x.len-len1-y.len+len2);
aa.len=a.len+x.len-len1-y.len+len2;
copy(tem_ac.num,tem_ac.num+tem_ac.len,new_ac.num+x.len-len1-y.len+len2);
new_ac.len=tem_ac.len+x.len-len1-y.len+len2;
cdab=mul(c+d,aa+b)-new_ac-tem_bd;
}
else{
Num bb,new_bd;
copy(b.num,b.num+b.len,bb.num+y.len-len2-x.len+len1);
bb.len=b.len+y.len-len2-x.len+len1;
copy(tem_bd.num,tem_bd.num+tem_bd.len,new_bd.num+y.len-len2-x.len+len1);
new_bd.len=tem_bd.len+y.len-len2-x.len+len1;
cdab=mul(c+d,a+bb)-tem_ac-new_bd;
}
// cout<<“临时cdab “<<cdab<<” “;
copy(tem_ac.num,tem_ac.num+tem_ac.len,ac.num+x.len-len1+y.len-len2);
ac.len=tem_ac.len+y.len-len2+x.len-len1;
int minlen=min(x.len-len1,y.len-len2);
copy(cdab.num,cdab.num+cdab.len,fin_cdab.num+minlen);
fin_cdab.len=cdab.len+minlen;
ans=ac+fin_cdab;
ans=ans+tem_bd;
while(ans.len>1 && !ans.num[ans.len-1]) –ans.len;
// cout<<“debug:”<<“a=”<<a<<” b=”<<b<<” c=”<<c<<” d=”<<d<<” ac=”<<ac<<” cdab=”<<fin_cdab<<” bd=”<<tem_bd<<endl;
return ans;
}
friend Num operator*(const Num &x,const Num &y){
return mul(x,y);
}
};
int main()
{
string a,b;
while(cin>>a>>b){
Num x=a,y=b;
cout<<“***************************************************”<<endl;
cout<<a<<endl<<“*”<<endl<<b<<endl<<“=”<<endl<<x*y<<endl;
cout<<“***************************************************”<<endl;
}
return 0;
}
