import java.io.*;
import java.math.BigDecimal;
import java.math.BigInteger;
import java.util.*;

public class Main {
    public static Read scanner = new Read(System.in);
    public static final long MOD = (long) (1e9 + 7);
    public static final int MID = (int) (1 * 1e5 + 7);
    public static final long LMAX = Long.MAX_VALUE;
    public static final long LMIN = Long.MIN_VALUE;
    public static final int IMAX = Integer.MAX_VALUE;
    public static final int IMIN = Integer.MIN_VALUE;
    public static int[] arr = new int[MID];
//    public static long[] Qz = new long[MID];
//    public static long[] Hz = new long[MID];
    public static int N, M , n , m;
    public static long ans;
//    public static boolean[][] stack = new boolean[MID][MID];
    //四个方向
    public static int[] row = {1, -1, 0, 0};
    public static int[] cos = {0, 0, 1, -1};
    static PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(System.out)));
    public static ArrayList<Integer>[] list = new ArrayList[MID];
    public static int[][] va = new int[MID][105];
    public static boolean[] pool = new boolean[MID];
    public static void solve(){
        n = scanner.nextInt();
        int m = scanner.nextInt();
        int q = scanner.nextInt();
        int min = IMAX;
        for(int i = 0 ; i <= n ; i++) list[i] = new ArrayList<>();
        for(int i = 1 ; i <= n ; i++) {arr[i] = scanner.nextInt();min = Math.min(min , arr[i]);}
        for(int i = 1 ; i <= m ; i++){
            int a = scanner.nextInt();
            int b = scanner.nextInt();
            list[a].add(b);
            list[b].add(a);
        }

        for(int i = 0 ; i <= n ; i++) Arrays.fill(va[i] , IMAX);
        for(int i = 1 ; i <= 100 ; i++){
            Arrays.fill(pool , 1 , n + 1 , false);
            bfs(i);
        }

        for(int i = 1 ; i <= q ; i++){
            int pi = scanner.nextInt();
            int ai = scanner.nextInt();
            ans = IMAX;
            for(int j = 0 ; j <= ai ; j++) ans = Math.min(ans , va[pi][j]);
            if(ans == IMAX){
                out.println(-1);
            } else {
                out.println(ans);
            }
        }


    }
    public static void bfs(int o){
        Queue<way> queue = new ArrayDeque<>();
        for(int i = 1 ; i <= n ; i++){
            if(arr[i] == o) {
                queue.add(new way(i , 0));
                va[i][o] = 0;
                pool[i] = true;
            }
        }
        while(!queue.isEmpty()){
            way w = queue.poll();
            int in = w.iq;
            int cnt = w.cnt + 1;
            for(Integer i : list[in]){
                if(pool[i]) continue;
                va[i][o] = Math.min(va[i][o] , cnt);
                pool[i] = true;
                queue.add(new way(i , cnt));
            }
        }
    }
    public static void main(String[] args) {
        int T = 1;
//        long start = System.currentTimeMillis();//程序开始时间戳
        while (T-- != 0) {
            solve();
        }
        out.flush();
//        long end = System.currentTimeMillis();//程序结束时间戳
//        out.println("运行时间 : " + (end - start));//输出运行时间
    }
    //快读
    static class Read {
        BufferedReader br;
        StringTokenizer st;

        public Read(InputStream in) {
            br = new BufferedReader(new InputStreamReader(in), 16384);
            eat("");
        }

        public void eat(String s) {
            st = new StringTokenizer(s);
        }

        public String nextLine() {
            try {
                return br.readLine();
            } catch (IOException e) {
                System.out.println("            ");
                return null;
            }
        }

        public boolean hasNext() {
            while (!st.hasMoreTokens()) {
                String s = nextLine();
                if (s == null)
                    return false;
                eat(s);
            }
            return true;
        }

        public String next() {
            hasNext();
            return st.nextToken();
        }

        public int nextInt() {
            return Integer.parseInt(next());
        }

        public long nextLong() {
            return Long.parseLong(next());
        }

        public Double nextDouble() {
            return Double.parseDouble(next());
        }

        public BigInteger nextBigInteger() {
            return new BigInteger(next());
        }

        public BigDecimal nextBigDecimal() {
            return new BigDecimal(next());
        }
    }
    public static void swap(long[] arr , int index1 , int index2){
        long t = arr[index1];
        arr[index1] = arr[index2];
        arr[index2] = t;
    }
    public static long Dot_pitch(long x , long y , long xx , long yy){
        return (xx - x) * (xx - x) + (yy - y) * (yy - y);
//        return (long) Math.sqrt(Math.pow(xx - x , 2) + Math.pow(yy - y , 2));
    }
}

class way {
    public int iq ,cnt;

    public way(int iq , int cnt) {
        this.iq = iq;
        this.cnt = cnt;
    }
}