[Link] https://www.acmicpc.net/problem/1009
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import java.util.*;
import java.io.*;
public class Main {
static BufferedReader br;
static StringBuilder sb = new StringBuilder();
static int div = 998244353;
public static void main(String[] args) throws IOException {
br = new BufferedReader(new InputStreamReader(System.in));
int test = toi(br.readLine());
int[] arr;
for(int iter = 0; iter < test; iter++) {
arr = getArr();
int a = (arr[0] % 10), b = arr[1];
if(a == 0) {
sb.append("10\n");
continue;
}
int t = getT(a, 10);
b = b % t;
int ans = a;
if(b == 0) b = t;
for(int i = 1; i < b; i++) ans = (ans * a) % 10;
sb.append(ans == 0 ? 10 : ans).append("\n");
}
print(sb);
}
static int getT(int a, int mod) {
int val = (a * a) % mod, t = 1;
while(val != a) {
val = (val * a) % mod;
t++;
}
return t;
}
static int toi(String s) { return Integer.parseInt(s); }
static long tol(String s) { return Long.parseLong(s); }
static String[] getLine() throws IOException { return br.readLine().split(" "); }
static int[] getArr() throws IOException { return Arrays.stream(br.readLine().split(" ")).mapToInt(Integer::parseInt).toArray(); }
static <T> void print(T s) { System.out.print(s); }
static <T> void println(T s) { System.out.println(s); }
}