#include <iostream>
#include <algorithm>
#include <time.h>
#include <vector>

using namespace std;

struct t {
 int y, x;
};

bool operator< (const t& a, const t& b) {
 return a.y < b.y;
}

ostream& operator << (ostream& stream, t &k) {
 stream << '(' << k.x << ',' << k.y << ')';
 return stream;
}

int main (int argc, char const* argv[]) {
 srand(time(NULL));
 vector<t> a;
 a.resize(10);
 for (int i = 0; i < a.size(); i += 1) {
  a[i].x = rand() % 100;
  a[i].y = rand() % 100;
  cout << a[i] << ' ';
 }
 cout << endl;
 sort(a.begin(), a.end());
 for (int i = 0; i < a.size(); i += 1)
  cout << a[i] << ' ';
 return 0;
}