[{"sectionTitle":"题目描述","type":"Text","text":"原题来自：2009 Multi-University Training Contest 12 - Host by FZU\r\n\r\n给你无向图的 $N$ 个点和 $M$ 条边，保证这 $M$ 条边都不同且不会存在同一点的自环边，现在问你至少要几笔才能所有边都画一遍。（一笔画的时候笔不离开纸）","subType":"markdown"},{"sectionTitle":"输入格式","type":"Text","text":"多组数据，每组数据用空行隔开。 \r\n对于每组数据，第一行两个整数 $N,M$ 表示点数和边数。接下去 $M$ 行每行两个整数 $a,b$，表示 $a,b$ 之间有一条边。","subType":"markdown"},{"sectionTitle":"输出格式","type":"Text","text":"对于每组数据，输出答案。","subType":"markdown"},{"sectionTitle":"样例","type":"Sample","text":"","subType":"markdown","payload":["3 3\n1 2\n2 3\n1 3\n\n4 2\n1 2\n3 4","1\n2"]},{"sectionTitle":"数据范围与提示","type":"Text","text":"$1 \\le N \\le 10^5,0 \\le M \\le 2\\times 10^5,1 \\le a,b \\le N$","subType":"markdown"}]