At the opening of the diplomatic mission of Russia

At the opening of the diplomatic mission of Russia

At the opening of the diplomatic mission of Russia in the territory of state A, the authorities of state A did not agree with the estimated number of embassy staff - 200 people and proposed to reduce it to 150 people.
Questions:
How are headcount issues regulated by the 1961 Vienna Convention?
How can this situation be resolved?

Additional information:

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