Generator for 322E

#include <cstdio>
#include <vector>
#include <utility>

using namespace std;

typedef std::pair<int,int> pii;

int main()
{
    int n = 1, last = 1;
    vector <pii> ed;
    for (int i = 2; n + i <= 100000; ++i)
    {
        ed.push_back(pii(last, n + 1));
        last = ++n;
        for (int j = 1; j < i; ++j, ++n)
            ed.push_back(pii(n, n + 1));
    }

    printf("%d\n", n);
    for (int i = 0; i < int(ed.size()); ++i)
        printf("%d %d\n", ed[i].first, ed[i].second);

    return 0;
}