{"problem":{"name":"Maintain Multiple Sequences","description":{"content":"There are $N$ sequences of integers.   The $i$\\-th $(1 \\leq i \\leq N)$ sequence has $L_i$ terms; the $j$\\-th $(1 \\leq j \\leq L_i)$ term of the $i$\\-th sequence is $a_{i, j}$. You are given $Q$ queries","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc271_b"},"statements":[{"statement_type":"Markdown","content":"There are $N$ sequences of integers.  \nThe $i$\\-th $(1 \\leq i \\leq N)$ sequence has $L_i$ terms; the $j$\\-th $(1 \\leq j \\leq L_i)$ term of the $i$\\-th sequence is $a_{i, j}$.\nYou are given $Q$ queries. For the $k$\\-th $(1 \\leq k \\leq Q)$ query, given integers $s_k$ and $t_k$, find the $t_k$\\-th term of the $s_k$\\-th sequence.\n\n## Constraints\n\n*   $1 \\leq N, Q \\leq 2 \\times 10^5$\n*   $L_i \\geq 1 \\, (1 \\leq i \\leq N)$\n*   $\\sum_{i=1}^N L_i \\leq 2 \\times 10^5$\n*   $1 \\leq a_{i, j} \\leq 10^9 \\, (1 \\leq i \\leq N, 1 \\leq j \\leq L_i)$\n*   $1 \\leq s_k \\leq N, 1 \\leq t_k \\leq L_{s_k} \\, (1 \\leq k \\leq Q)$\n*   All values in the input are integers.\n\n## Input\n\nThe input is given from Standard Input in the following format:\n\n$N$ $Q$\n$L_1$ $a_{1, 1}$ $\\ldots$ $a_{1, L_1}$\n$\\vdots$\n$L_N$ $a_{N, 1}$ $\\ldots$ $a_{N, L_N}$\n$s_1$ $t_1$\n$\\vdots$ \n$s_Q$ $t_Q$\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc271_b","tags":[],"sample_group":[["2 2\n3 1 4 7\n2 5 9\n1 3\n2 1","7\n5\n\nThe $1$\\-st sequence is $(1, 4, 7)$ and the $2$\\-nd is $(5, 9)$.  \nThe answer to each query is as follows:\n\n*   The $3$\\-rd term of the $1$\\-st sequence is $7$.\n*   The $1$\\-st term of the $2$\\-nd sequence is $5$."],["3 4\n4 128 741 239 901\n2 1 1\n3 314 159 26535\n1 1\n2 2\n3 3\n1 4","128\n1\n26535\n901"]],"created_at":"2026-03-03 11:01:13"}}