int main(int argc, char *argv[])
{
int t,i,a;
long b;
scanf("%d",&t);
for(i=0;i<t;i++) {
scanf("%d %ld",&a,&b);
printf("%d\n",lastdig(a,b));
}
return 0;
}
typedef long long ll;static int loop[]={1,1,4,4,2,1,1,4,4,2};static int last[]={0,1,6,1,6,5,6,1,6,1};static inline int lastdig(int a,ll b){ int b10=a%10; int lp=loop[b10]; int lst=1,t; if(b<lp){ t=b; while(t>0){ lst=(lst*b10)%10; --t;} return lst;}else{ t=b%lp; while(t>0){ lst=(lst*b10)%10; --t;} return(lst*last[b10])%10;}}int main(){ int t; scanf("%d",&t); int a; ll b; while(t--){ scanf("%d%lld",&a,&b); printf("%d\n",lastdig(a,b));} return 0;}