I do not think german nazis were too motivated against africans, specially african-americans. They were ultra racist against Jewish and Slavic.
The American nazis were the ones obsessed with skin color against black people.
At least that's the impression I get when reading about those times.
3 is the lower number that could fit there. Other numbers could fit depending on how much erase there was, but 3 is the lowest, thus the safest guess.