题目描述 Children are taught to add multi-digit numbers from $right-to-left$ one digit at a time. Many find the $carry$ operation - in which a $1$ is carried from one digit position to be added to the next - to be a significant challenge. Your job is to count the number of $carry$ operations for each of a set of addition problems so that educators may assess their difficulty. 输入格式 Each line of input contains two unsigned integers less than $10$ digits. 输出格式 For each line of input except the last you should compute and print the number of $carry$ operations that would result from adding the two numbers, in the format shown below. 输入样例 123 456 输出样例 NO carry operation.