Preferably the day before, boil potato with skin for 15-20min, depending on their size. Check with a knife whether they are soft. Let them cool down, peel and cut into cubes about 1*1 cm.
2
Peel carrot, wash the celery stalk and cook them in salted water 10-15min until tender but not over cooked. Take them out from the water, let cool down and cut in small pieces.
3
Cut pickles in small cubes, chop the onion. Mix all ingredients carefully in a bowl, add mayonnaise, yogurt and chopped pickles, then salt and pepper.