#include<iostream>
using namespace std;
int main(){
string a;
int n;
cin>>a>>a;
n=a.length();
int v[n],v1[n],v2[2*n+1];
for(int i=0;i<n;i++)
{
v[i]=a[i];
v1[i]=a[i];
}
v1[n-1]--;
for(int i=n-1;i>0;i--)
{
if(v1[i<0])
{
v1[i-1]--;
v1[i]+=10;
}
}
for(int i=0;i<2*n+1;i++)
{
v2[i]=0;
}
for(int i=n-1;i>=0;i--)
{
for(int j=n-1;j>=0;j--)
{
v2[j+i+2]+=2*v1[j]*v[i];
}
for(int i=2*n;i>0;i--)
{
v2[i-1]+=v2[i]/10;
v2[i]=v2[i]%10;
}
}
n=2*n+1;
int t=0;
for(t;a[t]==0;t++){}//測出第幾位開始不為0
for(int i=t;i<n;i++)
{
cout<<v2[i];
}
cout<<endl;
return 0;
}
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