A project has 75 activities but we have only a partial information as shown below:
activity = H, duration = 24 days, IP = not given
activity = N, duration = 27 days, IP = not given
activity = R, duration = 28 days, IP = not given
activity = K, duration = 43 days, IP = H, N
activity = P, duration = 52 days, IP = H, N
activity = C, duration = 53 days, IP = R
If LF(K) = 155, LF(P) = 161 and LF(C) = 121, find the value of LS(R).