Don't count your chickens before they hatch

nʲe ɡʌvʌrʲɪ ɡop pʌkɑ nʲe pʲirʲipryɡnʲiʃ

In Russian Не говори «гоп», пока не перепрыгнешь

This idiom is a Russian proverb that advises against celebrating before the task is completed.