static void Main()
{
SourceExpander.Expander.Expand();
// https://atcoder.jp/contests/practice2/tasks/practice2_j
var line = Console.ReadLine().Split(' ');
var N = int.Parse(line[0]);
var Q = int.Parse(line[1]);
var seg = new Segtree <long, Op>(Console.ReadLine().Split(' ').Select(long.Parse).ToArray());
for (int q = 0; q < Q; q++)
{
line = Console.ReadLine().Split(' ');
int t = int.Parse(line[0]);
int l = int.Parse(line[1]) - 1;
int r = int.Parse(line[2]);
switch (t)
{
case 1:
seg[l] = r;
break;
case 2:
Console.WriteLine(seg.Prod(l, r));
break;
case 3:
Console.WriteLine(1 + seg.MaxRight(l, num => num < r));
break;
}
}
}
