A little boy Gerald entered a clothes shop and found out something very unpleasant: not all clothes turns out to match. For example, Gerald noticed that he looks rather ridiculous in a smoking suit and a baseball cap.

Overall the shop sells n clothing items, and exactly m pairs of clothing items match. Each item has its price, represented by an integer number of rubles. Gerald wants to buy three clothing items so that they matched each other. Besides, he wants to spend as little money as possible. Find the least possible sum he can spend.

Input

The first input file line contains integers n and m — the total number of clothing items in the shop and the total number of matching pairs of clothing items (<image>).

Next line contains n integers ai (1 ≤ ai ≤ 106) — the prices of the clothing items in rubles.

Next m lines each contain a pair of space-separated integers ui and vi (1 ≤ ui, vi ≤ n, ui ≠ vi). Each such pair of numbers means that the ui-th and the vi-th clothing items match each other. It is guaranteed that in each pair ui and vi are distinct and all the unordered pairs (ui, vi) are different.

Output

Print the only number — the least possible sum in rubles that Gerald will have to pay in the shop. If the shop has no three clothing items that would match each other, print "-1" (without the quotes).

Examples

Input

3 3
1 2 3
1 2
2 3
3 1


Output

6


Input

3 2
2 3 4
2 3
2 1


Output

-1


Input

4 4
1 1 1 1
1 2
2 3
3 4
4 1


Output

-1

Note

In the first test there only are three pieces of clothing and they all match each other. Thus, there is only one way — to buy the 3 pieces of clothing; in this case he spends 6 roubles.

The second test only has three pieces of clothing as well, yet Gerald can't buy them because the first piece of clothing does not match the third one. Thus, there are no three matching pieces of clothing. The answer is -1.

In the third example there are 4 pieces of clothing, but Gerald can't buy any 3 of them simultaneously. The answer is -1.
import static java.lang.Math.*;
import java.util.*;
import java.io.*;

public class A {

    public void solve() throws Exception {
        
        int n=nextInt(), m=nextInt();
        int[] p = nextArr(n);
        boolean[][] b = new boolean[150][150];
        for (int i=0; i<m; ++i) {
            int a=nextInt(), aa=nextInt();
            b[a][aa]=b[aa][a]=true;
        }
        
        long res = INFL;
        
        for (int i=1; i<=n; ++i) for (int j=i+1; j<=n; ++j) for (int k=j+1; k<=n; ++k)
            if (b[i][j] && b[j][k] && b[i][k])
                res = minL(res,p[i-1]+p[j-1]+p[k-1]);
        
        println(res==INFL ? -1:res);
        
    }

    

    ////////////////////////////////////////////////////////////////////////////

    boolean showDebug = true;

    double EPS = 1e-7;
    int INF = Integer.MAX_VALUE;
    long INFL = Long.MAX_VALUE;
    double INFD = Double.MAX_VALUE;

    
    int absPos(int i) {
        return i<0 ? 0:i;
    }
    long absPos(long i) {
        return i<0 ? 0:i;
    }
    double absPos(double i) {
        return i<0 ? 0:i;
    }
    
    int min(int... nums) {
        int r = INF;
        for (int i: nums)
            if (i<r) r=i;
        return r;
    }
    int max(int... nums) {
        int r = -INF;
        for (int i: nums)
            if (i>r) r=i;
        return r;
    }
    long minL(long... nums) {
        long r = INFL;
        for (long i: nums)
            if (i<r) r=i;
        return r;
    }
    long maxL(long... nums) {
        long r = -INFL;
        for (long i: nums)
            if (i>r) r=i;
        return r;
    }
    double minD(double... nums) {
        double r = INFD;
        for (double i: nums)
            if (i<r) r=i;
        return r;
    }
    double maxD(double... nums) {
        double r = -INFD;
        for (double i: nums)
            if (i>r) r=i;
        return r;
    }
    long sumArr(int[] arr) {
        long res = 0;
        for (int i: arr)
            res+=i;
        return res;
    }
    long sumArr(long[] arr) {
        long res = 0;
        for (long i: arr)
            res+=i;
        return res;
    }
    double sumArr(double[] arr) {
        double res = 0;
        for (double i: arr)
            res+=i;
        return res;
    }

    long partsFitCnt(long partSize, long wholeSize) {
        return (partSize+wholeSize-1)/partSize;
    }

    boolean odd(long i) {
        return (i&1)==1;
    }

    long binpow(int x, int n) {
        long r = 1;
        while (n>0) {
            if ((n&1)!=0) r*=x;
            x*=x;
            n>>=1;
        }
        return r;
    }

    boolean isLetter(char c) {
        return (c>='a' && c<='z') || (c>='A' && c<='Z');
    }
    boolean isLowercase(char c) {
        return (c>='a' && c<='z');
    }
    boolean isUppercase(char c) {
        return (c>='A' && c<='Z');
    }
    boolean isDigit(char c) {
        return (c>='0' && c<='9');
    }
    
    String stringn(String s, int n) {
        if (n<1) return "";
        StringBuilder sb = new StringBuilder(s.length()*n);
        for (int i=0; i<n; ++i) sb.append(s);
        return sb.toString();
    }
    String str(Object o) {
        return o.toString();
    }


    long timer = System.currentTimeMillis();
    void startTimer() {
        timer = System.currentTimeMillis();
    }
    void stopTimer() {
        System.err.println("time: "+(System.currentTimeMillis()-timer)/1000.0);
    }


    class InputReader {
        private byte[] buf;
        private int bufPos = 0, bufLim = -1;
        public InputReader(int size) {
            buf = new byte[size];
            try {
                fillBuf();
            } catch (IOException e) {}
        }
        private void fillBuf() throws IOException {
            bufLim = System.in.read(buf);
            bufPos = 0;
        }
        char read() throws IOException {
            if (bufPos>=bufLim) fillBuf(); 
            return (char)buf[bufPos++];
        }
        boolean hasInput() throws IOException {
            if (bufPos>=bufLim) fillBuf();
            return bufPos<bufLim;
        }
    }

    InputReader in = new InputReader(1<<16);
    static BufferedWriter out = new BufferedWriter(new OutputStreamWriter(System.out), 1<<16);
    Formatter formatter = new Formatter(out);

    char nextChar() throws IOException {
        return in.read();
    }
    char nextNonWhitespaceChar() throws IOException {
        char c = in.read();
        while (c<=' ') c=in.read();
        return c;
    }
    String nextWord() throws IOException {
        StringBuilder sb = new StringBuilder();
        char c = in.read();
        while (c<=' ') c=in.read();
        while (c>' ') {
            sb.append(c);
            c = in.read();
        }
        return new String(sb);
    }
    String nextLine() throws IOException {
        StringBuilder sb = new StringBuilder();
        char c = in.read();
        while (c<=' ') c=in.read();
        while (c!='\n' && c!='\r') {
            sb.append(c);
            c = in.read();
        }
        return new String(sb);
    }
    int nextInt() throws IOException {
        int r = 0;
        char c = nextNonWhitespaceChar();
        boolean neg = false;
        if (c=='-') neg=true;
        else r=c-48;
        c = nextChar();
        while (c>='0' && c<='9') {
            r*=10;
            r+=c-48;
            c=nextChar();
        }
        return neg ? -r:r;
    }
    long nextLong() throws IOException {
        long r = 0;
        char c = nextNonWhitespaceChar();
        boolean neg = false;
        if (c=='-') neg=true;
        else r = c-48;
        c = nextChar();
        while (c>='0' && c<='9') {
            r*=10L;
            r+=c-48L;
            c=nextChar();
        }
        return neg ? -r:r;
    }
    double nextDouble() throws NumberFormatException, IOException {
        return Double.parseDouble(nextWord());
    }
    int[] nextArr(int size) throws NumberFormatException, IOException {
        int[] arr = new int[size];
        for (int i=0; i<size; i++)
            arr[i] = nextInt();
        return arr;
    }
    long[] nextArrL(int size) throws NumberFormatException, IOException {
        long[] arr = new long[size];
        for (int i=0; i<size; i++)
            arr[i] = nextLong();
        return arr;
    }
    double[] nextArrD(int size) throws NumberFormatException, IOException {
        double[] arr = new double[size];
        for (int i=0; i<size; i++)
            arr[i] = nextDouble();
        return arr;
    }
    String[] nextArrS(int size) throws NumberFormatException, IOException {
        String[] arr = new String[size];
        for (int i=0; i<size; i++)
            arr[i] = nextWord();
        return arr;
    }
    char[] nextArrCh(int size) throws IOException {
        char[] arr = new char[size];
        for (int i=0; i<size; i++)
            arr[i] = nextNonWhitespaceChar();
        return arr;
    }
    char[][] nextArrCh(int rows, int columns) throws IOException {
        char[][] arr = new char[rows][columns];
        for (int i=0; i<rows; i++)
            for (int j=0; j<columns; j++)
                arr[i][j] = nextNonWhitespaceChar();
        return arr;
    }

    void printf(String s, Object... o) {
        formatter.format(s, o);
    }
    void print(Object o) throws IOException {
        out.write(o.toString());
    }
    void println(Object o) throws IOException {
        out.write(o.toString());
        out.newLine();
    }
    void print(Object... o) throws IOException {
        for (int i=0; i<o.length; i++) {
            if (i!=0) out.write(' ');
            out.write(o[i].toString());
        }
    }
    void println(Object... o) throws IOException {
        print(o);
        out.newLine();
    }
    void printn(Object o, int n) throws IOException {
        String s = o.toString();
        for (int i=0; i<n; i++) {
            out.write(s);
            if (i!=n-1) out.write(' ');
        }
    }
    void printnln(Object o, int n) throws IOException {
        printn(o, n);
        out.newLine();
    }
    void printArr(int[] arr) throws IOException {
        for (int i=0; i<arr.length; i++) {
            if (i!=0) out.write(' ');
            out.write(Integer.toString(arr[i]));
        }
    }
    void printArr(long[] arr) throws IOException {
        for (int i=0; i<arr.length; i++) {
            if (i!=0) out.write(' ');
            out.write(Long.toString(arr[i]));
        }
    }
    void printArr(double[] arr) throws IOException {
        for (int i=0; i<arr.length; i++) {
            if (i!=0) out.write(' ');
            out.write(Double.toString(arr[i]));
        }
    }
    void printArr(String[] arr) throws IOException {
        for (int i=0; i<arr.length; i++) {
            if (i!=0) out.write(' ');
            out.write(arr[i]);
        }
    }
    void printArr(char[] arr) throws IOException {
        for (char c: arr) out.write(c);
    }
    void printlnArr(int[] arr) throws IOException {
        printArr(arr);
        out.newLine();
    }
    void printlnArr(long[] arr) throws IOException {
        printArr(arr);
        out.newLine();
    }
    void printlnArr(double[] arr) throws IOException {
        printArr(arr);
        out.newLine();
    }
    void printlnArr(String[] arr) throws IOException {
        printArr(arr);
        out.newLine();
    }
    void printlnArr(char[] arr) throws IOException {
        printArr(arr);
        out.newLine();
    }

    void debug(Object... o) {
        if (showDebug) System.err.println(Arrays.deepToString(o));
    }


    public static void main(String[] args) throws Exception {
        Locale.setDefault(Locale.US);
        new A().solve();
        out.flush(); out.close();
    }
}
