Capital gains on redemption of equity mutual fund scheme units after merger with another scheme

The Budget for 2018-19 has made certain changes in the taxation of LTCG on equity shares and equity mutual fund units. How should one calculate the LTCG on redemption of units of an equity mutual fund after merger of one scheme with another equity unit scheme with the same Mutual Fund, in the following example?
Name of equity fund scheme: E1, Year of purchase of units: 2016, Purchase price per unit: P, number of units purchased: N1.
Scheme E1 merges with another equity fund scheme E2 with the same Mutual Fund on 1.6.2018. Post-merger, all N1 units of E1 are cancelled and N2 new equity units in scheme E2 are allotted in proportion to the NAVs of the two schemes as on 1.6.2018.
                                                                     Scheme E1                   Scheme E2
1. Units held as on 31.5.2018                       N1                                  -----
2. NAV per unit as on 31.1.2018                   X1                                   X2
3. NAV per unit as on 1.6.2018                     Y1                                   Y2
4. Units held as on 1.6.2018 @                      ---                           N2=N1*Y1/Y2  [ @ =post merger]
5. Units to be redeemed on 30.6.2018           ---                         N3 (subject to Sec. Trn.Tax)    {N3<N2}
6. NAV per unit at which N3 are redeemed   ---                                      Y3                                                               
How does one calculate the LTCG on the N3 units to be redeemed on 30.6.2018?