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#14836. 跳跃

统计

Ballsout at Metal Frenzy Open Air 2022,图片来自 S. Bollmann, commons.wikimedia.org。

“The Unsightly Halfwits” 乐队正在他们的自然栖息地胡萨维克(Húsavík)举办一场狂野的音乐会。他们的主唱 Sveinn “Springheel” Jónsson 正以充沛的精力在舞台上跳跃,将每一个音符都变成一场视觉盛宴。但在如此混乱的蹦跳中保持节奏并非易事,你禁不住想知道他能坚持多久。

Sveinn 开始时的能量值为 $E$。这首歌每隔恰好 $N$ 毫秒就会有一个节拍。他的第一次跳跃在时刻 0 开始,与音乐完美同步。只要他的能量 $E$ 严格大于 0($E > 0$),每次跳跃就会持续恰好 $E$ 毫秒。当他的能量耗尽(即 $E = 0$)时,他会倒下,演出结束。如果他在落地后仍有能量,他会立即再次跃起进行下一次跳跃。当 Sveinn 恰好在节拍上落地时,他会因为纯粹的享受而获得 $+1$ 能量。但如果他稍微偏离了节拍,他的能量就会减少 1。

输入格式

输入包含:

  • 一行,包含两个整数 $N, E$,分别表示两次节拍之间的毫秒数以及主唱的初始能量值。这些数满足 $1 \le N \le 3 \cdot 10^5$ 且 $1 \le E \le 10^9$。

输出格式

输出一个整数,表示 Sveinn 停止跳跃前将过去多少毫秒。如果他永远不会停止,则输出 infinity

样例

样例输入 1

7 9

样例输出 1

59

样例输入 2

7 4

样例输出 2

infinity

样例输入 3

100001 123123123

样例输出 3

7581167638793024

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