n, k = map(int, input().split())
s = []
for i in range(n):#h:高さ
s.append([int(m) for m in input().split()])
count = 0
recli = []
if k == 2:
for i in range(n):
for j in range(i + 1, n):
larx = max(s[i][0], s[j][0])
smax = min(s[i][0], s[j][0])
lary = max(s[i][1], s[j][1])
smay = min(s[i][1], s[j][1])
rec = (larx - smax) * (lary - smay)
for l in range(n):
if smax <= s[l][0] <= larx and smay <= s[l][1] <= lary:
count += 1
if count >= k:
recli.append(rec)
count = 0
elif k == 3:
for i in range(n):
for j in range(i + 1, n):
for p in range(j + 1, n):
larx = max(s[i][0], s[j][0], s[p][0])
smax = min(s[i][0], s[j][0], s[p][0])
lary = max(s[i][1], s[j][1], s[p][1])
smay = min(s[i][1], s[j][1], s[p][1])
rec = (larx - smax) * (lary - smay)
for l in range(n):
if smax <= s[l][0] <= larx and smay <= s[l][1] <= lary:
count += 1
if count >= k:
recli.append(rec)
count = 0
else:
for i in range(n):
for j in range(i + 1, n):
for p in range(j + 1, n):
for q in range(p + 1, n):
larx = max(s[i][0], s[j][0], s[p][0], s[q][0])
smax = min(s[i][0], s[j][0], s[p][0], s[q][0])
lary = max(s[i][1], s[j][1], s[p][1], s[q][1])
smay = min(s[i][1], s[j][1], s[p][1], s[q][1])
rec = (larx - smax) * (lary - smay)
for l in range(n):
if smax <= s[l][0] <= larx and smay <= s[l][1] <= lary:
count += 1
if count >= k:
recli.append(rec)
count = 0
print(min(recli))