// 嘘三分探索
#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;

#include <atcoder/fenwicktree>

int main() {
    int M, K;
    cin >> M >> K;
    const int N = M * K;
    vector<int> A(N);
    vector<int> ord(N);
    vector<int> freq(M);
    vector<vector<int>> v2i(M);
    for (int i = 0; i < N; ++i) {
        cin >> A[i];
        ord[i] = A[i] + freq[A[i]] * M;
        v2i[A[i]].push_back(i);
        freq[A[i]]++;
    }

    auto eval = [&](int head_value) -> long long {
        atcoder::fenwick_tree<int> bit(N);
        long long ret = 0;
        for (int k = 0; k < K; ++k) {
            for (int i = 0; i < M; ++i) {
                int j = head_value + i;
                if (j >= M) j -= M;
                int x = v2i[j][k];
                ret += bit.sum(x, N);
                bit.add(x, 1);
            }
        }
        return ret;
    };
    int l = 0, r = M - 1;
    long long vl = eval(l), vr = eval(r);

    long long ret = min(vl, vr);
    while (l + 5 < r) {
        int cl = (l * 2 + r) / 3, cr = (l + r * 2) / 3;
        auto ecl = eval(cl), ecr = eval(cr);
        ret = min({ret, ecl, ecr});
        if (ecl < ecr) {
            r = cr;
            vr = ecr;
        } else {
            l = cl;
            vl = ecl;
        }
    }
    for (int i = l; i <= r; ++i) ret = min(ret, eval(i));

    cout << ret << '\n';
}