inf = float('inf')



N,K = list(map(int,input().split()))

ans = inf

X = []

Y = []

XY = []

for _ in range(N):

    x,y = list(map(int,input().split()))

    X.append(x)

    Y.append(y)

    XY.append((x,y))



X = sorted(X)

Y = sorted(Y)



for i in range(N):

    for j in range(i+1,N):

        for k in range(N):

            for l in range(k+1,N):

                cnt = 0

                for x, y in XY:

                    if X[i] <= x <= X[j] and Y[k] <= y <= Y[l]:

                        cnt += 1

                if cnt < K: continue

                S = (Y[l]-Y[k])*(X[j]-X[i])

                if S < ans:

                    ans = S



print(ans)
inf = float('inf')



N,K = list(map(int,input().split()))

ans = inf

X = []

Y = []

XY = []

for _ in range(N):

    x,y = list(map(int,input().split()))

    X.append(x)

    Y.append(y)

    XY.append((x,y))



X = sorted(X)

Y = sorted(Y)



for i, left in enumerate(X):

    for right in X[i+1:]:

        for j, bottom in enumerate(Y):

            for top in Y[j+1:]:

                cnt = 0

                for x, y in XY:

                    if left <= x <= right and bottom <= y <= top:

                        cnt += 1

                if cnt < K: continue

                S = (right-left)*(top-bottom)

                if S < ans:

                    ans = S



print(ans)
inf = float("inf")
N, K = list(map(int, input().split()))
ans = inf
X = []
Y = []
XY = []
for _ in range(N):
    x, y = list(map(int, input().split()))
    X.append(x)
    Y.append(y)
    XY.append((x, y))
X = sorted(X)
Y = sorted(Y)
for i in range(N):
    for j in range(i + 1, N):
        for k in range(N):
            for l in range(k + 1, N):
                cnt = 0
                for x, y in XY:
                    if X[i] <= x <= X[j] and Y[k] <= y <= Y[l]:
                        cnt += 1
                if cnt < K:
                    continue
                S = (Y[l] - Y[k]) * (X[j] - X[i])
                if S < ans:
                    ans = S
print(ans)

inf = float("inf")
N, K = list(map(int, input().split()))
ans = inf
X = []
Y = []
XY = []
for _ in range(N):
    x, y = list(map(int, input().split()))
    X.append(x)
    Y.append(y)
    XY.append((x, y))
X = sorted(X)
Y = sorted(Y)
for i, left in enumerate(X):
    for right in X[i + 1 :]:
        for j, bottom in enumerate(Y):
            for top in Y[j + 1 :]:
                cnt = 0
                for x, y in XY:
                    if left <= x <= right and bottom <= y <= top:
                        cnt += 1
                if cnt < K:
                    continue
                S = (right - left) * (top - bottom)
                if S < ans:
                    ans = S
print(ans)

-for i in range(N): -    for j in range(i + 1, N): -        for k in range(N): -            for l in range(k + 1, N): +for i, left in enumerate(X): +    for right in X[i + 1 :]: +        for j, bottom in enumerate(Y): +            for top in Y[j + 1 :]: -                    if X[i] <= x <= X[j] and Y[k] <= y <= Y[l]: +                    if left <= x <= right and bottom <= y <= top: -                S = (Y[l] - Y[k]) * (X[j] - X[i]) +                S = (right - left) * (top - bottom)