题目描述：

Problem #3560 - ECNU Online Judgehttps://acm.ecnu.edu.cn/problem/3560/

AC代码：

直接用long double解决，注意输入输出格式是%Lf

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
using namespace std;

int main(){
	long double a,b;
	scanf("%Lf%Lf",&a,&b);
	long long c=a/b;
	printf("%.9Lf\n",a-b*c);
}