{"problem":{"name":"123 Triangle","description":{"content":"Given is a sequence of $N$ digits $a_1a_2\\ldots a_N$, where each element is $1$, $2$, or $3$. Let $x_{i,j}$ defined as follows: *   $x_{1,j} := a_j$ $\\quad$ ($1 \\leq j \\leq N$) *   $x_{i,j} := | x_{i","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"agc043_b"},"statements":[{"statement_type":"Markdown","content":"Given is a sequence of $N$ digits $a_1a_2\\ldots a_N$, where each element is $1$, $2$, or $3$. Let $x_{i,j}$ defined as follows:\n\n*   $x_{1,j} := a_j$ $\\quad$ ($1 \\leq j \\leq N$)\n*   $x_{i,j} := | x_{i-1,j} - x_{i-1,j+1} |$ $\\quad$ ($2 \\leq i \\leq N$ and $1 \\leq j \\leq N+1-i$)\n\nFind $x_{N,1}$.\n\n## Constraints\n\n*   $2 \\leq N \\leq 10^6$\n*   $a_i = 1,2,3$ $(1 \\leq i \\leq N)$\n\n## Input\n\nInput is given from Standard Input in the following format:\n\n$N$\n$a_1$$a_2$$\\ldots$$a_N$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"agc043_b","tags":[],"sample_group":[["4\n1231","1\n\n$x_{1,1},x_{1,2},x_{1,3},x_{1,4}$ are respectively $1,2,3,1$.\n$x_{2,1},x_{2,2},x_{2,3}$ are respectively $|1-2| = 1,|2-3| = 1,|3-1| = 2$.\n$x_{3,1},x_{3,2}$ are respectively $|1-1| = 0,|1-2| = 1$.\nFinally, $x_{4,1} = |0-1| = 1$, so the answer is $1$."],["10\n2311312312","0"]],"created_at":"2026-03-03 11:01:13"}}