#include <bits/stdc++.h>
using namespace std;
#define ull unsigned long long int
ull modulo(ull a,ull b,ull c)
{
ull x=1;
while(b!=0)
{
if(b&1)
x=modulo(x,a,c);
a=modulo(a,a,c);
b>>=1;
}
return x;
}
int main() {
// your code goes here
int t;
scanf("%d",&t);
while(t--)
{
ull a,b;
scanf("%llu %llu",&a,&b);
cout<<modulo(a,b,10)<<endl;
}
return 0;
}
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