using System;
using System.Collections.Generic;
using System.Linq;

// https://yukicoder.me/problems/no/2563
class Program
{
    static string InputPattern = "InputX";

    static List<string> GetInputList()
    {
        var WillReturn = new List<string>();

        if (InputPattern == "Input1") {
            WillReturn.Add("5 6");
            WillReturn.Add("1 2 2 2 1");
            WillReturn.Add("1 2");
            WillReturn.Add("1 3");
            WillReturn.Add("1 4");
            WillReturn.Add("3 4");
            WillReturn.Add("4 5");
            WillReturn.Add("2 5");
            //2
        }
        else if (InputPattern == "Input2") {
            WillReturn.Add("4 2");
            WillReturn.Add("1 1 2 4");
            WillReturn.Add("1 2");
            WillReturn.Add("1 3");
            //0
        }
        else if (InputPattern == "Input3") {
            WillReturn.Add("8 9");
            WillReturn.Add("1 8 1 2 1 3 3 2");
            WillReturn.Add("6 3");
            WillReturn.Add("3 2");
            WillReturn.Add("4 3");
            WillReturn.Add("5 7");
            WillReturn.Add("7 3");
            WillReturn.Add("2 7");
            WillReturn.Add("2 1");
            WillReturn.Add("1 4");
            WillReturn.Add("4 7");
            //4
        }
        else {
            string wkStr;
            while ((wkStr = Console.ReadLine()) != null) WillReturn.Add(wkStr);
        }
        return WillReturn;
    }

    static void Main()
    {
        List<string> InputList = GetInputList();

        long[] wkArr = { };
        Action<string> SplitAct = pStr =>
            wkArr = pStr.Split(' ').Select(pX => long.Parse(pX)).ToArray();

        SplitAct(InputList[0]);
        long NodeCnt = wkArr[0];

        var InsUnionFind = new UnionFind();
        for (long I = 1; I <= NodeCnt; I++) {
            InsUnionFind.MakeSet(I);
        }

        long[] CArr = InputList[1].Split(' ').Select(pX => long.Parse(pX)).ToArray();

        // ノード色[ノード]なDict
        var ColorDict = new Dictionary<long, long>();

        // ノードのList[色]なDict
        var NodeListDict = new Dictionary<long, List<long>>();
        for (long I = 0; I <= CArr.GetUpperBound(0); I++) {
            long CurrColor = CArr[I];

            ColorDict[I + 1] = CurrColor;

            if (NodeListDict.ContainsKey(CurrColor) == false) {
                NodeListDict[CurrColor] = new List<long>();
            }
            NodeListDict[CurrColor].Add(I + 1);
        }

        foreach (string EachStr in InputList.Skip(2)) {
            SplitAct(EachStr);
            long FromNode = wkArr[0];
            long ToNode = wkArr[1];
            if (ColorDict[FromNode] == ColorDict[ToNode]) {
                InsUnionFind.Unite(FromNode, ToNode);
            }
        }

        long Answer = 0;
        foreach (long EachColor in NodeListDict.Keys) {
            long FirstNode = NodeListDict[EachColor][0];

            for (int I = 1; I <= NodeListDict[EachColor].Count - 1; I++) {
                long Root1 = InsUnionFind.FindSet(FirstNode);
                long Root2 = InsUnionFind.FindSet(NodeListDict[EachColor][I]);
                if (Root1 != Root2) {
                    Answer++;
                    InsUnionFind.Unite(Root1, Root2);
                }
            }
        }
        Console.WriteLine(Answer);
    }
}

#region UnionFind
// UnionFindクラス
internal class UnionFind
{
    private class NodeInfoDef
    {
        internal long ParentNode;
        internal long Rank;
    }
    private Dictionary<long, NodeInfoDef> mNodeInfoDict =
        new Dictionary<long, NodeInfoDef>();

    // 要素が1つである木を森に追加
    internal void MakeSet(long pNode)
    {
        NodeInfoDef WillAdd = new NodeInfoDef();
        WillAdd.ParentNode = pNode;
        WillAdd.Rank = 0;
        mNodeInfoDict[pNode] = WillAdd;
    }

    // 合併処理
    internal void Unite(long pX, long pY)
    {
        long XNode = FindSet(pX);
        long YNode = FindSet(pY);
        long XRank = mNodeInfoDict[XNode].Rank;
        long YRank = mNodeInfoDict[YNode].Rank;

        if (XRank > YRank) {
            mNodeInfoDict[YNode].ParentNode = XNode;
        }
        else {
            mNodeInfoDict[XNode].ParentNode = YNode;
            if (XRank == YRank) {
                mNodeInfoDict[YNode].Rank++;
            }
        }
    }

    // ノードを引数として、木の根を取得
    internal long FindSet(long pTargetNode)
    {
        // 根までの経路上のノードのList
        var PathNodeList = new List<long>();

        long CurrNode = pTargetNode;
        while (CurrNode != mNodeInfoDict[CurrNode].ParentNode) {
            PathNodeList.Add(CurrNode);
            CurrNode = mNodeInfoDict[CurrNode].ParentNode;
        }

        // 経路圧縮 (親ポインタの付け替え)
        foreach (long EachPathNode in PathNodeList) {
            mNodeInfoDict[EachPathNode].ParentNode = CurrNode;
        }
        return CurrNode;
    }

    internal void DebugPrint()
    {
        foreach (var EachPair in mNodeInfoDict.OrderBy(pX => pX.Key)) {
            Console.WriteLine("mNodeInfoDict[{0}].ParentNode={1}",
                EachPair.Key, EachPair.Value.ParentNode);
        }
    }
}
#endregion