from collections import defaultdict
N,M = map(int,input().split())
C = list(map(int,input().split()))
if len(set(C)) == len(C):
    print(0)
    exit()


par = [i for i in range(N+1)]
#parはparent親のこと
#par[x]の値がその木の根＝親を表す
#print(par)
def find(x):
    if par[x] == x:
        return x
    else:
        par[x] = find(par[x])
        #ここ経路圧縮 テクニックですよねえ
        return par[x]

def same(x,y):
    return find(x) == find(y)

def same_print(x,y):
    if find(x) == find(y):
        print(x)
    else:
        return False
    #これ微妙か？intが返されるか
    # Falseが返されるかわかんない上に
    # 0だとFalseになるの最悪かも

def unite(x,y):
    x = find(x)
    y = find(y)
    if x == y:
        return 0
    if par[x] < par[y]:
        x,y = y,x
    par[x] = y

def members(x):
    root = find(x)
    return [i for i in range(N) if find(i) == root]

def roots():
    return [i for i,x in enumerate(par) if x == i]

def group_count():
    k = roots()
    return len(k)

def all_group_menbers():
    group_members = defaultdict(list)
    for member in range(N):
        group_members[find(member)].append(member)
    return group_members

for m in range(M):
    u,v = map(int,input().split())
    if C[u-1] == C[v-1]:
        unite(u,v)

print(group_count()-1 - len(set(C)))
#print(graph)
#print(C)
#print(set(C))
#print(len(set(C)))
#print(par)
#print(set(par))
#print(len(set(par))-1)