def EstSemvar(x, h):
    ans = 0
    for i in range(len(x)-h):
        ans+=((x[i]-x[i+h])**2)
    return ans/(2*(len(x)-h))

def EstCov(x, h):
    ans = 0
    m = np.mean(x)
    for i in range(len(x)-h):
        ans+=((x[i]-m)*(x[i+h]-m))
    return ans/(len(x)-h)

print(EstSemvar(df.iloc[:,0].values, 1))
print(EstCov(df.iloc[:,0].values, 1))