#nullable enable

#region
void O(object? value) { if (value != null) Console.WriteLine(value); }
var _input = Array.Empty<string>();
var _iter = 0;
string String()
{
    while (_iter >= _input.Length) (_input, _iter) = (Console.ReadLine()!.Split(' '), 0);
    return _input[_iter++];
}
T I<T>() where T : IParsable<T> => T.Parse(String(), null);
#endregion

T[] Range<T>(int n, Func<T> F) => Enumerable.Range(0, n).Select(_ => F()).ToArray();
string Join<T>(IEnumerable<T> values, string? sep = null) => string.Join(sep ?? Environment.NewLine, values);

O(99);
for (var i = 1; i < 100; i++) O(i + " " + (i + 1));