用递归调用和辗转相除法求两个整数的最大公约数（输入多组数据，每个数在1到1000之间；输出为一行一个公约数）。-Calculate and output the greatest common divisor (GCD) of a pair of integers.The classic algorithm for computing the GCD, known as Euclid’s algorithm, goes as follows: Let m and n be variables containing the two numbers. If n is 0, then stop: m contains the GCD.Use recursion.(There will be multiple input sets. The line contains two integer between 1 and 1000. For each test case, output one line.)