#include <algorithm> #include <cstdio> #include <vector> using namespace std; using i64 = long long; int main() { int n, mod; scanf("%d %d", &n, &mod); int total = 0; vector<int> cnt(mod, 0); for (int i = 1; i <= n; ++i) { int b; scanf("%d", &b); if (b == 1) { ++cnt[i % mod]; ++total; } } printf("%d\n", total - *max_element(cnt.begin(), cnt.end())); return 0; }