#include <cstdio>

#define FOR(i, l, r) for(int i = (l)    ; i <  (r); i++)
#define REV(i, l, r) for(int i = (r) - 1; i >= (l); i--)
#define INC0(i, n) FOR(i, 0, n)
#define INC1(i, n) FOR(i, 1, (n) + 1)
#define DEC0(i, n) REV(i, 0, n)
#define DEC1(i, n) REV(i, 1, (n) + 1)

typedef long long   signed int LL;
typedef long long unsigned int LU;


struct Ave {
	int sum, num;
	bool operator<(const Ave& obj) {
		return (this -> sum) * obj.num < obj.sum * (this -> num);
	}
};

int n, k, a[9];
int b[9];
Ave ave[9];

int ex(int a, int b) {
	return b == 0 ? 1 : a * ex(a, b - 1);
}

int main() {
	scanf("%d%d", &n, &k);
	INC0(i, n) { scanf("%d", &a[i]); }
	
	Ave max = {   0, 1}; 
	Ave min = {1001, 1};
	
	INC0(i, ex(k, n)) {
		int t = i;
		INC0(j, n) {
			b[j] = t % k;
			t /= k;
		}
		
		INC0(j, k) { ave[j].sum = ave[j].num = 0; }
		INC0(j, n) {
			ave[ b[j] ].sum += a[j];
			ave[ b[j] ].num ++;
		}
		
		INC0(j, k) {
			if(ave[j].num != 0 &&    ave[j] < min  ) { min = ave[j]; }
			if(ave[j].num != 0 && ! (ave[j] < max) ) { max = ave[j]; }
		}
	}
	
	printf("%d\n", (max.sum * min.num - min.sum * max.num) / (max.num * min.num));
	
	return 0;
}