#include <iostream>
using namespace std;
int main()
{
int t,ca,cb,a,b;
cin>>t;
for(int i=0;i<t;i++)
{
cin>>a>>b;
ca=a%10;
switch (ca)
{
case 0: cout<<0<<endl; break;
case 1: cout<<1<<endl; break;
case 5: cout<<5<<endl; break;
case 6: cout<<6<<endl; break;
case 2:
{
int c2;
c2=b%100;
if(c2%4==1)cout<<2<<endl;
else if(c2%4==2)cout<<4<<endl;
else if(c2%4==3)cout<<8<<endl;
else if(c2%4==0)cout<<6<<endl;
break;
}
case 3:
{
int c2;
c2=b%100;
if(c2%4==1)cout<<3<<endl;
else if(c2%4==2)cout<<9<<endl;
else if(c2%4==3)cout<<7<<endl;
else if(c2%4==0)cout<<1<<endl;
break;
}
case 4:
{
cb==b%10;
if(cb%2==0)cout<<6<<endl;
else cout<<4<<endl;
break;
}
case 7:
{
int c2;
c2=b%100;
if(c2%4==1)cout<<7<<endl;
else if(c2%4==2)cout<<9<<endl;
else if(c2%4==3)cout<<3<<endl;
else if(c2%4==0)cout<<1<<endl;
break;
}
case 8:
{
int c2;
c2=b%100;
if(c2%4==1)cout<<8<<endl;
else if(c2%4==2)cout<<4<<endl;
else if(c2%4==3)cout<<2<<endl;
else if(c2%4==0)cout<<6<<endl;
break;
}
case 9:
{
cb==b%10;
if(cb%2==0)cout<<1<<endl;
else cout<<9<<endl;
break;
}
}
}
return 0;
}
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