# 1 2 4 7 9 15 100
# | 1 | 2 | 3 | 2 | 5 | 85 | --f
# 3 5 5 7 90 --t
# 3, 5 -- x < x-1 + x-2
# | 3 | 5 | 7 | 90 |
# 8
# sort(t)
# output << t[n]
n, m = map(int, input().split())
n = list(map(int, input().split()))
#f = []
t = []
l = len(n)
k = n[0]
b = 0
f = 0
for i in range(1, l, 2):
b = n[i]
f = b - k
k = n[i]
t.append(f)
#b = n[i + 1]
#f = b - k
g = []
for i in range(1, l - 1):
g.append(t[i] - t[i - 1])
l = len(g)
while(m > 0):
if(m <= g // 2):
t = sorted(t)
t = sorted(t)
l = len(t)
if(m < l):
m -= l
n = []
for i in range(0, l, 2):
n.append(t[i])
t = []
l = len(n)
else:
m = 0
print(t[m-1])
#end
