#include<cstdio>
//abs part can be fixed...
long long a[3005];
long long sum[3005];
long long f[3005][3005];
struct Element{
    int p;
    long value;
    Element(int p=0,long long value=0):p(p),value(value){}
};
Element queue[3005][1005][2];
int h[3005][2], t[3005][2];

long long abs(long long u){ return u>0?u:-u; }

long long max(long long a,long long b){ return a>b?a:b; }

int main(){
    int n,m,k;
    scanf("%d%d%d",&n,&k,&m);
    sum[0] = 0;
    for(int i = 1; i <= n; i++){
        scanf("%lld",&a[i]);
        sum[i] = sum[i-1]+a[i];
    }
    long long inf = 1e15+7;
    for(int i = 0; i <= k; i++){ 
        f[0][i] = -inf;
        h[i][0] = h[i][1] = 0;
        t[i][0] = t[i][1] = -1;
    }
    f[0][0] = 0;
    queue[0][++t[0][0]][0] = Element(0,0);
    queue[0][++t[0][1]][1] = Element(0,0);
    for(int i = 1; i <= n; i++){
        f[i][0] = -inf;
        for(int j = 1; j <= k; j++){
            f[i][j] = -inf;
            /*for(int last = max(0,i-m); last <= i-1; last++){
                //f[i][j] = max(f[i][j],f[last][j-1]+abs(sum[i]-sum[last]));
                //f[i][j] = max(f[i][j],f[last][j-1]+sum[i]-sum[last]);
                //f[i][j] = max(f[i][j],f[last][j-1]-sum[i]+sum[last]);
            }*/
            while(h[j-1][0]<=t[j-1][0] && queue[j-1][h[j-1][0]][0].p<i-m) h[j-1][0]++;
            while(h[j-1][1]<=t[j-1][1] && queue[j-1][h[j-1][1]][1].p<i-m) h[j-1][1]++;
            long long res0 = -inf, res1 = -inf;
            if(h[j-1][0]<=t[j-1][0]) res0 = queue[j-1][h[j-1][0]][0].value+sum[i];
            if(h[j-1][1]<=t[j-1][1]) res1 = queue[j-1][h[j-1][1]][1].value-sum[i];
            f[i][j] = max(res0,res1);
            //printf("f[%d][%d] = %lld\n",i,j,f[i][j]);
            //update
        }
        for(int j = 1; j <= k; j++){
            long long value = f[i][j]-sum[i];
            while(t[j][0]>=0 && value>=queue[j][t[j][0]][0].value) t[j][0]--;
            queue[j][++t[j][0]][0] = Element(i,value);
            value = f[i][j]+sum[i];
            while(t[j][1]>=0 && value>=queue[j][t[j][1]][1].value) t[j][1]--;
            queue[j][++t[j][1]][1] = Element(i,value);
        }
    }
    printf("%lld\n",f[n][k]);
    return 0;
}