{"problem":{"name":"Find by Query","description":{"content":"This is an **interactive task**, where your program and the judge interact via Standard Input and Output. The judge has a string of length $N$ consisting of $0$ and $1$: $S = S_1S_2\\ldots S_N$. Here, ","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc299_d"},"statements":[{"statement_type":"Markdown","content":"This is an **interactive task**, where your program and the judge interact via Standard Input and Output.\nThe judge has a string of length $N$ consisting of $0$ and $1$: $S = S_1S_2\\ldots S_N$. Here, $S_1 = 0$ and $S_N = 1$.\nYou are given the length $N$ of $S$, but not the contents of $S$. Instead, you can ask the judge at most $20$ questions as follows.\n\n*   Choose an integer $i$ such that $1 \\leq i \\leq N$ and ask the value of $S_i$.\n\nPrint an integer $p$ such that $1 \\leq p \\leq N-1$ and $S_p \\neq S_{p+1}$.  \nIt can be shown that such $p$ always exists under the settings of this problem.\n\n## Constraints\n\n*   $2 \\leq N \\leq 2 \\times 10^5$\n\n## Input And Output\n\nFirst, receive the length $N$ of the string $S$ from Standard Input:\n\n$N$\n\nThen, you get to ask the judge at most $20$ questions as described in the problem statement.\nPrint each question to Standard Output in the following format, where $i$ is an integer satisfying $1 \\leq i \\leq N$:\n\n? $i$\n\nIn response to this, the value of $S_i$ will be given from Standard Input in the following format:\n\n$S_i$\n\nHere, $S_i$ is $0$ or $1$.\nWhen you find an integer $p$ satisfying the condition in the problem statement, print it in the following format, and immediately quit the program:\n\n! $p$\n\nIf multiple solutions exist, you may print any of them.\n\n[samples]\n\n## Notes\n\n*   **Print a newline and flush Standard Output at the end of each message. Otherwise, you may get a TLE verdict.**\n*   **If there is malformed output during the interaction or your program quits prematurely, the verdict will be indeterminate.**\n*   After printing the answer, immediately quit the program. Otherwise, the verdict will be indeterminate.\n*   The string $S$ will be fixed at the start of the interaction and will not be changed according to your questions or other factors.","is_translate":false,"language":"English"}],"meta":{"iden":"abc299_d","tags":[],"sample_group":[],"created_at":"2026-03-03 11:01:14"}}