import sys
from collections import deque

def main():
    N, K, M = map(int, sys.stdin.readline().split())
    A = list(map(int, sys.stdin.readline().split()))
    
    sums = [0] * (N + 1)
    for i in range(1, N + 1):
        sums[i] = sums[i-1] + A[i-1]
    
    INF = float('-inf')
    dp = [[INF] * (K + 1) for _ in range(N + 1)]
    dp[0][0] = 0
    
    for j in range(1, K + 1):
        max1_q = deque()  # (k, dp[k][j-1] - sums[k])
        max2_q = deque()  # (k, dp[k][j-1] + sums[k])
        max_i = min(j * M, N)
        for i in range(j, max_i + 1):
            k = i - 1
            if k >= 0 and dp[k][j-1] != INF:
                val1 = dp[k][j-1] - sums[k]
                while max1_q and max1_q[-1][1] <= val1:
                    max1_q.pop()
                max1_q.append((k, val1))
                
                val2 = dp[k][j-1] + sums[k]
                while max2_q and max2_q[-1][1] <= val2:
                    max2_q.pop()
                max2_q.append((k, val2))
            
            lower_bound = max(j-1, i - M)
            while max1_q and max1_q[0][0] < lower_bound:
                max1_q.popleft()
            while max2_q and max2_q[0][0] < lower_bound:
                max2_q.popleft()
            
            current_max = INF
            if max1_q:
                current_max = max(current_max, max1_q[0][1] + sums[i])
            if max2_q:
                current_max = max(current_max, max2_q[0][1] - sums[i])
            
            if current_max != INF:
                dp[i][j] = current_max
    
    print(dp[N][K])

if __name__ == "__main__":
    main()