list_of_top3_hills.cpp

#include <set>
#include <iostream>

int main(){
    std::set<int> hills;
    for(int ii = 0; ii < 10; ii++){
        int temp;
        std::cin >> temp;
        hills.insert(temp);
    }
    std::set<int>::reverse_iterator it = hills.rbegin();
    for(int ii = 0; ii < 3; ii++){
        std::cout << *it++ << std::endl;
    }
    
}