[Link] https://AtCoder.jp/contests/abc235/tasks/abc235_c
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import java.util.*;
import java.io.*;
public class Main {
static BufferedReader br;
static int max = 0, maxIdx = 0;
public static void main(String[] args) throws IOException {
br = new BufferedReader(new InputStreamReader(System.in));
String[] line = getLine();
StringBuilder sb = new StringBuilder();
int n = toi(line[0]), q = toi(line[1]);
HashMap<Integer, ArrayList<Integer>> hm = new HashMap<>();
line = getLine();
for(int i = 0; i < n; i++) {
if(!hm.containsKey(toi(line[i]))) hm.put(toi(line[i]), new ArrayList<Integer>());
hm.get(toi(line[i])).add(i + 1);
}
for(int i = 0; i < q; i++) {
line = getLine();
int x = toi(line[0]), k = toi(line[1]);
if(!hm.containsKey(x) || hm.get(x).size() <= k - 1) sb.append("-1\n");
else sb.append(hm.get(x).get(k - 1)).append("\n");
}
print(sb);
}
static int toi(String s) { return Integer.parseInt(s); }
static String[] getLine() throws IOException { return br.readLine().split(" "); }
static <T> void print(T s) { System.out.print(s); }
static <T> void println(T s) { System.out.println(s); }
}