s = input()
n, m = map(int, s.split(' '))
s = input()
a = list(map(int, s.split(' ')))
for _ in range(m):
    d = list(map(int, input().split(' ')))
    t, l, r = d[0], d[1], d[2]
    if t == 1:
        x, y = d[3], d[4]
        a = a[:l] + [y if i == x else i for i in a[l:r+1]] + a[r:]
    else:
        k = d[3]
        b = sorted(set(a))
        s = 0
        for c in b:
            if k + s < c:
                print(k + s)
                break
            s += 1
        else:
            print(k + s)