#include <stdio.h>
#define MAX(a,b) ((a)>(b)?(a):(b))
#define NMAX 100010
#define INF 666000666

int V[NMAX], N, K, Kk, Dmin[NMAX], Dmax[NMAX], DifMax, Pmin[NMAX], Pmax[NMAX];

int main()
{
        int i, lomax=0, himax=1, lomin=0, himin=1;

        freopen("vila2.in", "r", stdin);
        scanf("%d %d", &N, &K);
        if (K>N) K = N;

        for (i = 1; i <= N; i++) scanf("%d", V+i);
	K = 2*K;

        Dmin[0] = INF;
        for (i = 1; i <= K; i++)
        {
                while (V[i]>Dmax[himax-1] && himax>0) himax--;
                Dmax[himax]=V[i]; Pmax[himax++]=i;
                while (V[i]<Dmin[himin-1] && himin>0) himin--;
                Dmin[himin]=V[i]; Pmin[himin++]=i;
        }
        DifMax = Dmax[0]-Dmin[0];

        for (i = K+1; i <= N; i++)
        {
                if (i-Pmin[lomin]>K) lomin++;
                if (i-Pmax[lomax]>K) lomax++;
                while (V[i]>Dmax[himax-1] && himax>lomax) himax--;
                Dmax[himax]=V[i]; Pmax[himax++]=i;
                while (V[i]<Dmin[himin-1] && himin>lomin) himin--;
                Dmin[himin]=V[i]; Pmin[himin++]=i;
                DifMax = MAX(DifMax, Dmax[lomax]-Dmin[lomin]);
        }

        freopen("vila2.out", "w", stdout);
        printf("%d\n", DifMax);

        return 0;
        
}