By Giulio Piovaccari MILAN (Reuters) -Pirelli said on Tuesday it had sought alternative suppliers, increased stocks and shifted production since March to mitigate the impact of Russia’s invasion of Ukraine. Russia, where the Italian tyremaker operates two plants, accounts for around 3% of Pirelli’s revenues and around 11% of its total car tyre capacity, especially in the standard segment, with about half of that intended for export. Pirelli, which on Tuesday said its operating profit grew 35% in the first quarter, said previously it had halted investments in Russia, excluding those linked to s…