CF92A.Chips

There are n walruses sitting in a circle. All of them are numbered in the clockwise order: the walrus number 2 sits to the left of the walrus number 1, the walrus number 3 sits to the left of the walrus number 2, ..., the walrus number 1 sits to the left of the walrus number n.

The presenter has m chips. The presenter stands in the middle of the circle and starts giving the chips to the walruses starting from walrus number 1 and moving clockwise. The walrus number i gets i chips. If the presenter can't give the current walrus the required number of chips, then the presenter takes the remaining chips and the process ends. Determine by the given n and m how many chips the presenter will get in the end.

有 $n$ 只海象围成一个圆圈坐好。它们均按顺时针方向编号：海象编号 2 坐在海象编号 1 的左侧，海象编号 3 坐在海象编号 2 的左侧，……，海象编号 1 坐在海象编号 $n$ 的左侧。

主持人手中有 $m$ 枚筹码。主持人站在圆圈中心，从编号为 1 的海象开始，按顺时针方向依次向海象分发筹码。编号为 $i$ 的海象将获得 $i$ 枚筹码。如果主持人无法向当前海象提供所需数量的筹码，则主持人收回剩余的所有筹码，过程结束。给定 $n$ 和 $m$，请确定主持人最终能收回多少枚筹码。

The first line contains two integers n and m (1 ≤ n ≤ 50, 1 ≤ m ≤ 104) — the number of walruses and the number of chips correspondingly.

第一行包含两个整数 $n$ 和 $m$（$1 ≤ n ≤ 50$，$1 ≤ m ≤ 10^4$）—— 分别表示海象的数量和筹码的数量。

Print the number of chips the presenter ended up with.

输出主持人最终拥有的筹码数量。

In the first sample the presenter gives one chip to the walrus number 1, two chips to the walrus number 2, three chips to the walrus number 3, four chips to the walrus number 4, then again one chip to the walrus number 1. After that the presenter runs out of chips. He can't give anything to the walrus number 2 and the process finishes.

In the third sample the presenter gives one chip to the walrus number 1, two chips to the walrus number 2, three chips to the walrus number 3, then again one chip to the walrus number 1. The presenter has one chip left and he can't give two chips to the walrus number 2, that's why the presenter takes the last chip.

在第一个样例中，主持人给1号海象1枚筹码，给2号海象2枚筹码，给3号海象3枚筹码，给4号海象4枚筹码，然后再次给1号海象1枚筹码。此后主持人手中的筹码用尽，无法再给2号海象任何筹码，整个过程结束。

在第三个样例中，主持人给1号海象1枚筹码，给2号海象2枚筹码，给3号海象3枚筹码，然后再次给1号海象1枚筹码。此时主持人还剩下1枚筹码，但由于无法凑出2枚筹码给2号海象，主持人便收回了最后一枚筹码。