{"problem":{"name":"Foods Loved by Everyone","description":{"content":"Katsusando loves omelette rice. Besides, he loves crème brûlée, tenderloin steak and so on, and believes that these foods are all loved by everyone. To prove that hypothesis, he conducted a survey on ","description_type":"Markdown"},"platform":"AtCoder","limit":{"time_limit":2000,"memory_limit":262144},"difficulty":"None","is_remote":true,"is_sync":true,"sync_url":null,"sign":"abc118_b"},"statements":[{"statement_type":"Markdown","content":"Katsusando loves omelette rice.\nBesides, he loves crème brûlée, tenderloin steak and so on, and believes that these foods are all loved by everyone.\nTo prove that hypothesis, he conducted a survey on $M$ kinds of foods and asked $N$ people whether they like these foods or not.\nThe $i$\\-th person answered that he/she only likes the $A_{i1}$\\-th, $A_{i2}$\\-th, $...$, $A_{iK_i}$\\-th food.\nFind the number of the foods liked by all the $N$ people.\n\n## Constraints\n\n*   All values in input are integers.\n*   $1 \\leq N, M \\leq 30$\n*   $1 \\leq K_i \\leq M$\n*   $1 \\leq A_{ij} \\leq M$\n*   For each $i$ $(1 \\leq i \\leq N)$, $A_{i1}, A_{i2}, ..., A_{iK_i}$ are distinct.\n\n## Constraints\n\nInput is given from Standard Input in the following format:\n\n$N$ $M$\n$K_1$ $A_{11}$ $A_{12}$ $...$ $A_{1K_1}$\n$K_2$ $A_{21}$ $A_{22}$ $...$ $A_{2K_2}$\n$:$\n$K_N$ $A_{N1}$ $A_{N2}$ $...$ $A_{NK_N}$\n\n## Output\n\nPrint the number of the foods liked by all the $N$ people.\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"abc118_b","tags":[],"sample_group":[["3 4\n2 1 3\n3 1 2 3\n2 3 2","1\n\nAs only the third food is liked by all the three people, $1$ should be printed."],["5 5\n4 2 3 4 5\n4 1 3 4 5\n4 1 2 4 5\n4 1 2 3 5\n4 1 2 3 4","0\n\nKatsusando's hypothesis turned out to be wrong."],["1 30\n3 5 10 30","3"]],"created_at":"2026-03-03 11:01:14"}}