class lazy_segtree:
    def update(self, k):
        self.d[k] = self.op(self.d[2 * k], self.d[2 * k + 1])

    def all_apply(self, k, f):
        self.d[k] = self.mapping(f, self.d[k])
        if k < self.size:
            self.lz[k] = self.composition(f, self.lz[k])

    def push(self, k):
        self.all_apply(2 * k, self.lz[k])
        self.all_apply(2 * k + 1, self.lz[k])
        self.lz[k] = self.identity

    def __init__(self, V, OP, E, MAPPING, COMPOSITION, ID):
        self.n = len(V)
        self.log = (self.n - 1).bit_length()
        self.size = 1 << self.log
        self.d = [E for i in range(2 * self.size)]
        self.lz = [ID for i in range(self.size)]
        self.e = E
        self.op = OP
        self.mapping = MAPPING
        self.composition = COMPOSITION
        self.identity = ID
        for i in range(self.n):
            self.d[self.size + i] = V[i]
        for i in range(self.size - 1, 0, -1):
            self.update(i)

    def set(self, p, x):
        assert 0 <= p and p < self.n
        p += self.size
        for i in range(self.log, 0, -1):
            self.push(p >> i)
        self.d[p] = x
        for i in range(1, self.log + 1):
            self.update(p >> i)

    def get(self, p):
        assert 0 <= p and p < self.n
        p += self.size
        for i in range(self.log, 0, -1):
            self.push(p >> i)
        return self.d[p]

    def prod(self, l, r):
        assert 0 <= l and l <= r and r <= self.n
        if l == r:
            return self.e
        l += self.size
        r += self.size
        for i in range(self.log, 0, -1):
            if ((l >> i) << i) != l:
                self.push(l >> i)
            if ((r >> i) << i) != r:
                self.push(r >> i)
        sml, smr = self.e, self.e
        while l < r:
            if l & 1:
                sml = self.op(sml, self.d[l])
                l += 1
            if r & 1:
                r -= 1
                smr = self.op(self.d[r], smr)
            l >>= 1
            r >>= 1
        return self.op(sml, smr)

    def all_prod(self):
        return self.d[1]

    def apply_point(self, p, f):
        assert 0 <= p and p < self.n
        p += self.size
        for i in range(self.log, 0, -1):
            self.push(p >> i)
        self.d[p] = self.mapping(f, self.d[p])
        for i in range(1, self.log + 1):
            self.update(p >> i)

    def apply(self, l, r, f):
        assert 0 <= l and l <= r and r <= self.n
        if l == r:
            return
        l += self.size
        r += self.size
        for i in range(self.log, 0, -1):
            if ((l >> i) << i) != l:
                self.push(l >> i)
            if ((r >> i) << i) != r:
                self.push((r - 1) >> i)
        l2, r2 = l, r
        while l < r:
            if l & 1:
                self.all_apply(l, f)
                l += 1
            if r & 1:
                r -= 1
                self.all_apply(r, f)
            l >>= 1
            r >>= 1
        l, r = l2, r2
        for i in range(1, self.log + 1):
            if ((l >> i) << i) != l:
                self.update(l >> i)
            if ((r >> i) << i) != r:
                self.update((r - 1) >> i)

    def max_right(self, l, g):
        assert 0 <= l and l <= self.n
        assert g(self.e)
        if l == self.n:
            return self.n
        l += self.size
        for i in range(self.log, 0, -1):
            self.push(l >> i)
        sm = self.e
        while 1:
            while l % 2 == 0:
                l >>= 1
            if not (g(self.op(sm, self.d[l]))):
                while l < self.size:
                    self.push(l)
                    l = 2 * l
                    if g(self.op(sm, self.d[l])):
                        sm = self.op(sm, self.d[l])
                        l += 1
                return l - self.size
            sm = self.op(sm, self.d[l])
            l += 1
            if (l & -l) == l:
                break
        return self.n

    def min_left(self, r, g):
        assert 0 <= r and r <= self.n
        assert g(self.e)
        if r == 0:
            return 0
        r += self.size
        for i in range(self.log, 0, -1):
            self.push((r - 1) >> i)
        sm = self.e
        while 1:
            r -= 1
            while r > 1 and (r % 2):
                r >>= 1
            if not (g(self.op(self.d[r], sm))):
                while r < self.size:
                    self.push(r)
                    r = 2 * r + 1
                    if g(self.op(self.d[r], sm)):
                        sm = self.op(self.d[r], sm)
                        r -= 1
                return r + 1 - self.size
            sm = self.op(self.d[r], sm)
            if (r & -r) == r:
                break
        return 0

def main():
    n, k = list(map(int, input().split()))
    last = int(input())-1
    A = list(map(lambda x: int(x)-1, input().split()))
    A[last] -= 1
    if A[last] < k: return []
    if min(A) < 0: return []
    ma = sum(A)
    N = n+1
    if ma % N: return []
    cnt = ma // N
    for i in range(n):
        A[i] -= cnt
        if A[i] < 0: return []
    sa = max(A)
    E = [[] for _ in range(sa+1)]
    LR = [[-1, -1] for _ in range(n)]
    for i in range(n):
        if not A[i]: continue
        E[A[i]].append(i)
    F = []
    for a in range(sa, 0, -1):
        for now in E[a]:
            LR[now][0] = len(F)
            for _ in range(a):
                F.append(now)
            LR[now][1] = len(F)
    nk = k
    B = [0] * n
    V = []
    for i in range(cnt):
        nk -= 1
        if B[F[i]] > nk: return []
        V.append(nk-B[F[i]])
        B[F[i]] += 1
    def op(a, b):
        return min(a, b)
    def mapp(a, b):
        return a+b
    def comp(a, b):
        return a+b
    st = lazy_segtree(V, op, 1<<60, mapp, comp, 0)
    Ans = []
    NG = [1] * cnt
    for now in range(n):
        l, r = LR[now]
        for m in range(l, r):
            if st.prod(0, m) == 0:
                break
            Ans.append(now)
            st.apply(0, m, -1)
            st.set(m, 1<<60)
            NG[m] = 0
    for i in range(cnt):
        if NG[i]:
            Ans.append(F[i])
    Ans.append(last)
    X = [0] * n
    nk = k
    for i in range(cnt-1):
        now = F[i]
        if nk <= X[now]: assert 0
        X[now] += 1
        nk -= 1
    return [ans+1 for ans in Ans]

Ans = main()
if Ans:
    print(len(Ans))
    print(*Ans)
else:
    print(-1)