{"problem":{"name":"Toll Gates","description":{"content":"There are $N + 1$ squares arranged in a row, numbered $0, 1, ..., N$ from left to right. Initially, you are in Square $X$. You can freely travel between adjacent squares. Your goal is to reach Square ","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc094_b"},"statements":[{"statement_type":"Markdown","content":"There are $N + 1$ squares arranged in a row, numbered $0, 1, ..., N$ from left to right.\nInitially, you are in Square $X$. You can freely travel between adjacent squares. Your goal is to reach Square $0$ or Square $N$. However, for each $i = 1, 2, ..., M$, there is a toll gate in Square $A_i$, and traveling to Square $A_i$ incurs a cost of $1$. It is guaranteed that there is no toll gate in Square $0$, Square $X$ and Square $N$.\nFind the minimum cost incurred before reaching the goal.\n\n## Constraints\n\n*   $1 \\leq N \\leq 100$\n*   $1 \\leq M \\leq 100$\n*   $1 \\leq X \\leq N - 1$\n*   $1 \\leq A_1 < A_2 < ... < A_M \\leq N$\n*   $A_i \\neq X$\n*   All values in input are integers.\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$N$ $M$ $X$\n$A_1$ $A_2$ $...$ $A_M$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc094_b","tags":[],"sample_group":[["5 3 3\n1 2 4","1\n\nThe optimal solution is as follows:\n\n*   First, travel from Square $3$ to Square $4$. Here, there is a toll gate in Square $4$, so the cost of $1$ is incurred.\n*   Then, travel from Square $4$ to Square $5$. This time, no cost is incurred.\n*   Now, we are in Square $5$ and we have reached the goal.\n\nIn this case, the total cost incurred is $1$."],["7 3 2\n4 5 6","0\n\nWe may be able to reach the goal at no cost."],["10 7 5\n1 2 3 4 6 8 9","3"]],"created_at":"2026-03-03 11:01:14"}}