mod = 1000000007
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    class Bit:
        def __init__(self, n):
            self.size = n
            self.tree = [0] * (n + 1)

        def sum(self, i):
            s = 0
            while i > 0:
                s += self.tree[i]
                i -= i & -i
            return s

        def add(self, i, x):
            while i <= self.size:
                self.tree[i] += x
                i += i & -i

        def lower_bound(self, w):
            if w <= 0:
                return 0
            x = 0
            k = 1 << (self.size.bit_length() - 1)
            while k:
                if x + k <= self.size and self.tree[x + k] < w:
                    w -= self.tree[x + k]
                    x += k
                k >>= 1
            return x + 1

    M, K = map(int, input().split())
    N = M * K
    A = list(map(int, input().split()))

    idx = [[-1] * M for _ in range(K)]
    LV = [0] * M
    for i, a in enumerate(A):
        idx[LV[a]][a] = i + 1
        LV[a] += 1

    bit_cur = Bit(N)
    bit_all = Bit(N)
    base = 0
    score_sum = [0] * M
    for lv in range(K):
        I = idx[lv]
        score = [0] * M
        for a in range(M):
            i = I[a]
            base += M * lv - bit_all.sum(i)
            score[0] += a - bit_cur.sum(i)
            bit_cur.add(i, 1)
        for a in range(1, M):
            i = I[a - 1]
            x = bit_cur.sum(i) - 1
            score[a] = score[a - 1] - x + (M - (x + 1))

        # delete
        for a in range(M):
            i = I[a]
            bit_cur.add(i, -1)
            bit_all.add(i, 1)
            score_sum[a] += score[a]
    print(base + min(score_sum))


if __name__ == '__main__':
    main()