Thoroughly wash the leafy greens (sorrel, spinach, beet tops, goutweed and nettle) and put into a saucepan, adding cold water flush with the leaves. Bring to the boil and simmer for 30 minutes, slightly pressing the greens from time to time. Place the boiled leaves on a sieve, rub through and cool. Peel cucumbers and finely chop together with onions and dill. Salt a bit and rub with a wooden masher. Dilute the strained beet tops with cold kvass or sour shchi and add the mashed cucumbers and greens. Put an ice in botvinia and serve with fish, cut into thin slices and laid on a plate. Do not forget to put a saucer with ice on the table for those wishing could optionally add some.