```class Vector:

def __init__(self,k):
self.k = k
self.coordinates = [0] * k

def set(self,coordinates):
self.coordinates = coordinates
if len(self.coordinates) != self.k:
self.k = len(self.coordinates)

def set(self,idx,val):
if self.k > idx:
self.coordinates[idx] = val

if self.k == other.k:
result = Vector(self.k)
for i in range(self.k):
result.coordinates[i] = self.coordinates[i] + other.coordinates[i]
return result
else:
print "vectors with different size"

def  __sub__(self,other):
if self.k == other.k:
result = Vector(self.k)
for i in range(self.k):
result.coordinates[i] = self.coordinates[i] - other.coordinates[i]
return result
else:
print "vectors with different size"

def  __mul__(self,other):
if self.k == other.k:
result = 0
for i in range(self.k):
result  += self.coordinates[i] * other.coordinates[i]
return result
else:
print "vectors with different size"
return 0

def __repr__(self):
return str(self.coordinates)

vector_a = Vector(2)
vector_b = Vector(2)

vector_a.set(0,1)
vector_a.set(1,2)
vector_b.set(0,2)
vector_b.set(1,3)

print vector_a

print vector_b

vector_c = vector_a + vector_b
vector_d = vector_a - vector_b
vector_e = vector_a * vector_b
print vector_c
print vector_d
print vector_e```