const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;
void (async function () {
const n = Number(await readline());
const scores = (await readline()).split(" ").map(Number);
const k = Number(await readline());
const dp = new Array(n).fill(0);
dp[0] = scores[0];
for (let i = 1; i < n; i++) {
let max = -Infinity;
for (let j = i - 1; j >= Math.max(i - k, 0); j--) {
max = Math.max(max, dp[j]);
}
dp[i] = max + scores[i];
}
console.log(dp[n - 1]);
})();