#include <iostream> #include <string> #include <unordered_map> using namespace std; int main() { unordered_map<string, int> people = {{"John", 32}, {"Adele", 45}, {"Bo", 29}}; cout << "Before: " << people.size() << "\n"; people.erase("John"); cout << "After: " << people.size(); return 0; }