2 it only happens this way (nowadays)
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In a non-leap year, Yom Yerushalayim is the 235th day in the year if Heshvan is whole Haser (has 3029 days) and Kislev is Haserwhole (has 2930 days) or vice versa:

Tishrei - 30 days each
Heshvan, - 29 days
Kislev - 5930 days together
Tevet - 29 days
Shvat - 30 days
Adar - 29 days
Nisan - 30 days
Iyar - 28 days (Yom Yerushalayim is on the 28th day of Iyar)

In a non-leap year, Yom Yerushalayim is the 235th day in the year if Heshvan is whole (has 30 days) and Kislev is Haser (has 29 days) or vice versa:

Tishrei - 30 days each
Heshvan, Kislev - 59 days together
Tevet - 29 days
Shvat - 30 days
Adar - 29 days
Nisan - 30 days
Iyar - 28 days (Yom Yerushalayim is on the 28th day of Iyar)

In a non-leap year, Yom Yerushalayim is the 235th day in the year if Heshvan is Haser (has 29 days) and Kislev is whole (has 30 days):

Tishrei - 30 days
Heshvan - 29 days
Kislev - 30 days
Tevet - 29 days
Shvat - 30 days
Adar - 29 days
Nisan - 30 days
Iyar - 28 days (Yom Yerushalayim is on the 28th day of Iyar)

1
source | link

In a non-leap year, Yom Yerushalayim is the 235th day in the year if Heshvan is whole (has 30 days) and Kislev is Haser (has 29 days) or vice versa:

Tishrei - 30 days each
Heshvan, Kislev - 59 days together
Tevet - 29 days
Shvat - 30 days
Adar - 29 days
Nisan - 30 days
Iyar - 28 days (Yom Yerushalayim is on the 28th day of Iyar)