[{"sectionTitle":"题目描述","type":"Text","text":"来源：SDOI 2009 \r\n\r\nSheng Bill 有着惊人的心算能力，甚至能用大脑计算出两个巨大的数的 GCD（最大公约数）！因此他经常和别人比赛计算 GCD。有一天 Sheng Bill 很嚣张地找到了你，并要求和你比赛，但是输给 Sheng Bill 岂不是很丢脸！所以你决定写一个程序来教训他。","subType":"markdown"},{"sectionTitle":"输入格式","type":"Text","text":"输入共两行，第一行一个数 $A$，第二行一个数 $B$。","subType":"markdown"},{"sectionTitle":"输出格式","type":"Text","text":"一行，表示 $A$ 和 $B$ 的最大公约数。","subType":"markdown"},{"sectionTitle":"样例","type":"Sample","text":"","subType":"markdown","payload":["12\n54","6"]},{"sectionTitle":"数据范围与提示","type":"Text","text":"对于全部数据，$0\\lt A,B\\le 10^{10000}$。","subType":"markdown"}]