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#include <bits/stdc++.h>
using namespace std;

int n, k, q;

long long query(int l, int r, vector <long long>& prefsums){
	vector <long long> dp(n+1, 0);
	for(int i = l+k-1; i<=r; ++i){
		dp[i] = max(dp[i-1], dp[i-k]+prefsums[i]-prefsums[i-k]);
	}
	return dp[r];
}

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);

	cin >> n >> k >> q;

	int x;
	vector <long long> prefsums(n+1);

	prefsums[0] = 0;
	for(int i = 1; i<=n; ++i){
		cin >> x;
		prefsums[i] = prefsums[i-1]+x;
	}

	int l, r;
	for(int i = 0; i<q; ++i){
		cin >> l >> r;
		cout << query(l, r, prefsums) << "\n";
	}

}