int a[] = new int[100];
int b[] = new int[100];
Scanner skan = new Scanner(System.in);
int n = skan.nextInt();
for(int i=1; i<=n; i++){
a[i] = skan.nextInt();
b[i] = skan.nextInt();
}
for(int i=1; i<=n; i++)
System.out.println(potegowanie(a[i],b[i])%10);
static int potegowanie (int a, int b){
if(b==0)
return 1;
else
return a*potegowanie(a,b-1);
}