{"problem":{"name":"Face Produces Unhappiness","description":{"content":"There are $N$ people standing in a queue from west to east. Given is a string $S$ of length $N$ representing the directions of the people. The $i$\\-th person from the west is facing west if the $i$\\-t","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc140_d"},"statements":[{"statement_type":"Markdown","content":"There are $N$ people standing in a queue from west to east.\nGiven is a string $S$ of length $N$ representing the directions of the people. The $i$\\-th person from the west is facing west if the $i$\\-th character of $S$ is `L`, and east if that character of $S$ is `R`.\nA person is happy if the person in front of him/her is facing the same direction. If no person is standing in front of a person, however, he/she is not happy.\nYou can perform the following operation any number of times between $0$ and $K$ (inclusive):\nOperation: Choose integers $l$ and $r$ such that $1 \\leq l \\leq r \\leq N$, and rotate by $180$ degrees the part of the queue: the $l$\\-th, $(l+1)$\\-th, $...$, $r$\\-th persons. That is, for each $i = 0, 1, ..., r-l$, the $(l + i)$\\-th person from the west will stand the $(r - i)$\\-th from the west after the operation, facing east if he/she is facing west now, and vice versa.\nWhat is the maximum possible number of happy people you can have?\n\n## Constraints\n\n*   $N$ is an integer satisfying $1 \\leq N \\leq 10^5$.\n*   $K$ is an integer satisfying $1 \\leq K \\leq 10^5$.\n*   $|S| = N$\n*   Each character of $S$ is `L` or `R`.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$N$ $K$\n$S$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc140_d","tags":[],"sample_group":[["6 1\nLRLRRL","3\n\nIf we choose $(l, r) = (2, 5)$, we have `LLLRLL`, where the $2$\\-nd, $3$\\-rd, and $6$\\-th persons from the west are happy."],["13 3\nLRRLRLRRLRLLR","9"],["10 1\nLLLLLRRRRR","9"],["9 2\nRRRLRLRLL","7"]],"created_at":"2026-03-03 11:01:14"}}