{"problem":{"name":"Go Home","description":{"content":"There is a kangaroo at coordinate $0$ on an infinite number line that runs from left to right, at time $0$. During the period between time $i-1$ and time $i$, the kangaroo can either stay at his posit","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"arc070_a"},"statements":[{"statement_type":"Markdown","content":"There is a kangaroo at coordinate $0$ on an infinite number line that runs from left to right, at time $0$. During the period between time $i-1$ and time $i$, the kangaroo can either stay at his position, or perform a jump of length exactly $i$ to the left or to the right. That is, if his coordinate at time $i-1$ is $x$, he can be at coordinate $x-i$, $x$ or $x+i$ at time $i$. The kangaroo's nest is at coordinate $X$, and he wants to travel to coordinate $X$ as fast as possible. Find the earliest possible time to reach coordinate $X$.\n\n## Constraints\n\n*   $X$ is an integer.\n*   $1≤X≤10^9$\n\n## Input\n\nThe input is given from Standard Input in the following format:\n\n$X$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"arc070_a","tags":[],"sample_group":[["6","3\n\nThe kangaroo can reach his nest at time $3$ by jumping to the right three times, which is the earliest possible time."],["2","2\n\nHe can reach his nest at time $2$ by staying at his position during the first second, and jumping to the right at the next second."],["11","5"]],"created_at":"2026-03-03 11:01:14"}}