#include<bits/stdc++.h>
using namespace std;
#define int long long
const int maxn = 2010;
const int mod = 1e9 + 7;
int s[maxn];
int mx[maxn][maxn];
int f[maxn];
int n, k;
int ans = 0, pw = 1;
int type, seed;
signed main() {
	scanf("%lld%lld", &n, &k);
	for(int i = 1; i <= n; i++) {
		scanf("%lld", &s[i]);
		mx[i][i] = s[i];
	}
	for(int i = 1; i <= n; i++) {
		for(int j = i + 1; j <= n; j++) {
			mx[i][j] = max(mx[i][j - 1], s[j]);
		}
	}
	for(int i = 1; i <= n; i++) {
		f[i] = INT64_MAX;
		for(int j = max(0ll, i - k); j < i; j++) {
			f[i] = min(f[i], f[j] + mx[j + 1][i]);
		}
	}
	for(int i = n; i; i--, pw = 23 * pw % mod) {
		ans = (ans + 1ll * f[i] * pw % mod) % mod;
	}
	printf("%lld", ans);
}

implementer.cpp: In function ‘char nextch()’:
implementer.cpp:15:31: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   15 |     if (pos == BUF_SIZE) fread(buf, BUF_SIZE, 1, fin), pos = 0;
      |                          ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
answer.code: In function ‘int main()’:
answer.code:13:14: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   13 |         scanf("%lld%lld", &n, &k);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~
answer.code:15:22: warning: ignoring return value of ‘int scanf(const char*, ...)’ declared with attribute ‘warn_unused_result’ [-Wunused-result]
   15 |                 scanf("%lld", &s[i]);
      |                 ~~~~~^~~~~~~~~~~~~~~
/usr/bin/ld: /tmp/ccNrCBmE.o: in function `main':
answer.code:(.text.startup+0x0): multiple definition of `main'; /tmp/ccO2EddC.o:implementer.cpp:(.text.startup+0x0): first defined here
/usr/bin/ld: /tmp/ccO2EddC.o: in function `main':
implementer.cpp:(.text.startup+0x151): undefined reference to `solve(int, int, int*)'
collect2: error: ld returned 1 exit status