#include <bits/stdc++.h>
using namespace std;
#define incII(i, l, r) for(decay_t<decltype(r)> i = (l)    ; i <= (r); i++)
#define incIX(i, l, r) for(decay_t<decltype(r)> i = (l)    ; i <  (r); i++)
#define incXI(i, l, r) for(decay_t<decltype(r)> i = (l) + 1; i <= (r); i++)
#define incXX(i, l, r) for(decay_t<decltype(r)> i = (l) + 1; i <  (r); i++)
#define decII(i, l, r) for(decay_t<decltype(r)> i = (r)    ; i >= (l); i--)
#define decIX(i, l, r) for(decay_t<decltype(r)> i = (r) - 1; i >= (l); i--)
#define decXI(i, l, r) for(decay_t<decltype(r)> i = (r)    ; i >  (l); i--)
#define decXX(i, l, r) for(decay_t<decltype(r)> i = (r) - 1; i >  (l); i--)
#define inc(i, n)  incIX(i, 0, n)
#define dec(i, n)  decIX(i, 0, n)
#define inc1(i, n) incII(i, 1, n)
#define dec1(i, n) decII(i, 1, n)
auto inII = [](auto a, auto l, auto r) -> bool { return (l <= a && a <= r); };
auto inIX = [](auto a, auto l, auto r) -> bool { return (l <= a && a <  r); };
auto inXI = [](auto a, auto l, auto r) -> bool { return (l <  a && a <= r); };
auto inXX = [](auto a, auto l, auto r) -> bool { return (l <  a && a <  r); };
auto setmin   = [](auto & a, auto b) -> bool { return (b <  a ? a = b, true : false); };
auto setmax   = [](auto & a, auto b) -> bool { return (b >  a ? a = b, true : false); };
auto setmineq = [](auto & a, auto b) -> bool { return (b <= a ? a = b, true : false); };
auto setmaxeq = [](auto & a, auto b) -> bool { return (b >= a ? a = b, true : false); };
using LL = long long int;
using LD = long double;
#define PB push_back
#define EB emplace_back
#define MP make_pair
#define MT make_tuple
#define FI first
#define SE second
#define FR front()
#define BA back()
#define ALL(a) begin(a), end(a)
#define RALL(a) rbegin(a), rend(a)
#define RV(a) reverse(ALL(a))
#define ST(a) sort(ALL(a))
#define RST(a) sort(RALL(a))
#define SC static_cast
#define SI(a) SC<int>(a.size())
#define SL(a) SC<LL>(a.size())
#define RF(e, ...) for(auto && e: __VA_ARGS__)
#define SF(a, ...) for(auto && [__VA_ARGS__]: a)
#define until(...) while(not(__VA_ARGS__))
#define if_not(...) if(not(__VA_ARGS__))
#define ef else if
#define UR assert(false)
auto * IS = & cin;
auto * OS = & cout;
template<typename ... A> void in(A & ... a) { (* IS >> ... >> a); }
#define IN(...) __VA_ARGS__; in(__VA_ARGS__)
struct OS_init { OS_init() { * OS << boolalpha << fixed << setprecision(20); } } os_init_;
void                                      out_([[maybe_unused]] string const & s) { }
template<typename A                > void out_([[maybe_unused]] string const & s, A const & a) { * OS << a; }
template<typename A, typename ... B> void out_(                 string const & s, A const & a, B const & ... b) { * OS << a << s; out_(s, b ...); }
auto outF  = [](string const & s, string const & t, auto const & ... a) { out_(s, a ...); * OS << t << flush; };
auto outN  = [](auto const & ... a) { outF(""  , ""  , a ...); };
auto outS  = [](auto const & ... a) { outF(" " , " " , a ...); };
auto outL  = [](auto const & ... a) { outF("\n", "\n", a ...); };
auto outSN = [](auto const & ... a) { outF(" " , ""  , a ...); };
auto outNL = [](auto const & ... a) { outF(""  , "\n", a ...); };
auto outSL = [](auto const & ... a) { outF(" " , "\n", a ...); };
auto out   = outSL;
template<typename A                > void disp_(A const & a) { * OS << a; }
template<typename A, typename ... T> void disp_(A const & a, string const & s, T const & ... t) { string ss; for(auto && e: a) { * OS << ss; ss = s; disp_(e, t ...); } }
auto dispI = [](auto const & a, auto const & s, auto const & ... t) { disp_(a, t ...); * OS << s << flush; };
auto dispT = [](auto const & a, auto const & s, auto const & ... t) { for(auto && e: a) { disp_(e, t ...); * OS << s; } * OS << flush; };
auto dispL = [](auto const & a,                 auto const & ... t) { dispT(a, "\n", t ...); };
template<typename A> istream & operator>>(istream & is, vector<A>       & v) { for(auto && e: v) { is >> e; } return is; }
template<typename A> ostream & operator<<(ostream & os, vector<A> const & v) { string ss; for(auto && e: v) { os << ss << e; ss = " "; } return os; }
template<typename A                > auto make_v(A a) { return a; }
template<typename A, typename ... M> auto make_v(A a, int n, M ... m) { return vector(n, make_v(a, m ...)); }
template<typename A, typename ... N> auto read_v(N ... n) { auto a = make_v(A { }, n ...); in(a); return a; }
template<typename A, size_t N> istream & operator>>(istream & is, array<A, N>       & a) { for(auto && e: a) { is >> e; } return is; }
template<typename A, size_t N> ostream & operator<<(ostream & os, array<A, N> const & a) { string ss; for(auto && e: a) { os << ss << e; ss = " "; } return os; }
template<typename A, typename B> istream & operator>>(istream & is, pair<A, B>       & p) { return is >> p.first >> p.second; }
template<typename A, typename B> ostream & operator<<(ostream & os, pair<A, B> const & p) { return os << p.first << " " << p.second; }
template<int I = 0, typename T> void tin_ (istream & is, T       & t) { if constexpr(I < tuple_size<T>::value) { is >> get<I>(t); tin_<I + 1>(is, t); } }
template<int I = 0, typename T> void tout_(ostream & os, T const & t) { if constexpr(I < tuple_size<T>::value) { if(I != 0) { os << " "; } os << get<I>(t); tout_<I + 1>(os, t); } }
template<typename ... A> istream & operator>>(istream & is, tuple<A ...>       & t) { tin_ (is, t); return is; }
template<typename ... A> ostream & operator<<(ostream & os, tuple<A ...> const & t) { tout_(os, t); return os; }

// ---- ----

template<typename T> class SegmentTree {
private:
	int n, s;
	vector<T> a;
	function<T(T &, T &)> f;
	T e;
	bool ok;
	void shift(int & p) {
		assert(inIX(p, 0, n));
		p += s;
	}
public:
	SegmentTree() { n = 0; }
	SegmentTree(int nn, function<T(T &, T &)> ff, T ee) { init(nn, ff, ee); }
	void init(int nn, function<T(T &, T &)> ff, T ee) {
		n = nn;
		f = ff;
		e = ee;
		s = 1;
		while(s < n) { s *= 2; }
		a = vector<T>(2 * s, e);
		ok = true;
	}
	void apply(int p, function<void(T &)> g) {
		shift(p);
		g(a[p]);
		while(p > 1) {
			p /= 2;
			a[p] = f(a[2 * p], a[2 * p + 1]);
		}
	}
	T fold_IX(int l, int r) {
		assert(ok);
		assert(inII(l, 0, n)); l += s;
		assert(inII(r, 0, n)); r += s; r--;
		T x = e, y = e;
		while(l <= r) {
			if(l % 2 == 1) { x = f(x, a[l]); l++; }
			if(r % 2 == 0) { y = f(a[r], y); r--; }
			l /= 2;
			r /= 2;
		}
		return f(x, y);
	}
	T fold_II(int l, int r) { return fold_IX(l + 0, r + 1); }
	T fold_XI(int l, int r) { return fold_IX(l + 1, r + 1); }
	T fold_XX(int l, int r) { return fold_IX(l + 1, r + 0); }
	const T & operator[](int p) {
		shift(p);
		return a[p];
	}
	T & ref(int p) {
		shift(p);
		ok = false;
		return a[p];
	}
	void calc() {
		dec(i, s) { a[i] = f(a[2 * i], a[2 * i + 1]); }
		ok = true;
	}
};
#define OP(s) [&](auto & A, auto & B) { return s; }
#define AP(s) [&](auto & A) { s; }

// ----

int main() {
	int IN(n, k);
	SegmentTree<LL> st(n + 2, OP(min(A, B)), 1e12);
	LL ans = 0;
	st.ref(0) = 0;
	inc1(i, n) {
		LL IN(a);
		st.ref(i) = a;
		ans += a;
	}
	st.ref(n + 1) = 0;
	st.calc();
	
	inc1(i, n + 1) { st.apply(i, AP(A += st.fold_IX(max(i - k, 0), i))); }
	out(ans - st[n + 1]);
}