0 to stop trying to do something because you have realized that you cannot succeed: --
Three of the original five candidates for the Democratic presidential nomination have now thrown in the towel.
1 to admit that you are defeated or cannot do something any more: --
We can complete it step by step however long the road is and it can't be completed however short the road is if you don't even mark your footprint.
Можем да го завършим стъпка по стъпка, колкото и дълъг да е пътят и не може да бъде завършен, колкото и кратък да е пътят, ако дори не маркирате отпечатъка си.