Modulo Operator (%) gives divergent results

Given this Example:

std::vector<int> numbers = {5,6,7}; //size is 3
int i = -1; 
std::cout << i % 3 <<"\n";                  // output: -1
std::cout << i % numbers.size() << "\n";    // output: 0

basically in both statements im processing -1 % 3 but the compiler outputs different numbers. I don't understand this outcome, maybe someone can explain it to me.