Mishnayos Nazir Perek 3 Mishnah 2

One who accepted two terms of naziriteship shaves at the close of the first naziriteship on the thirty-first day, and at the close of the second term on the sixty-first day. Since his second term of naziriteship begins after shaving on the thirty-first day, the sixty-first day of the first term is the thirty-first day of his second term. And if he shaved for the first term on the thirtieth day, he shaves for the second term on the sixtieth day, which is the thirty-first day after the start of his second term of naziriteship. And if he shaved for the second term on day sixty less one, he has fulfilled his obligation, as this is the thirtieth day of his second term. And this testimony was attested to by Rabbi Pappeyas, who heard from his teachers with regard to one who vowed to observe two terms of naziriteship, that if he shaved for the first term on the thirtieth day, he shaves for the second term on the sixtieth day. And if he shaved for the second term on the day sixty less one, he has fulfilled his obligation, because the thirtieth day of the first term of naziriteship counts as part of his tally of the second term.

מִי שֶׁנָּזַר שְׁתֵּי נְזִירִיּוֹת, מְגַלֵּחַ אֶת הָרִאשׁוֹנָה יוֹם שְׁלשִׁים וְאֶחָד, וְאֶת הַשְּׁנִיָּה יוֹם שִׁשִּׁים וְאֶחָד. וְאִם גִּלַּח אֶת הָרִאשׁוֹנָה יוֹם שְׁלשִׁים, מְגַלֵּחַ אֶת הַשְּׁנִיָּה יוֹם שִׁשִּׁים. וְאִם גִּלַּח יוֹם שִׁשִּׁים חָסֵר אֶחָד, יָצָא. וְזוֹ עֵדוּת הֵעִיד רַבִּי פַּפְּיַס עַל מִי שֶׁנָּזַר שְׁתֵּי נְזִירִיּוֹת, שֶׁאִם גִּלַּח אֶת הָרִאשׁוֹנָה שְׁלשִׁים יוֹם, מְגַלֵּחַ אֶת הַשְּׁנִיָּה יוֹם שִׁשִּׁים. וְאִם גִּלַּח לְיוֹם שִׁשִּׁים חָסֵר אֶחָד, יָצָא, שֶׁיּוֹם שְׁלשִׁים עוֹלֶה לוֹ מִן הַמִּנְיָן: