#include<iostream> // cin\cout\endl #include<cstdio> //scanf()\printf() #include<cstring> // strcpy()\strcat()\strcmp()\strlen()\memset() #include<cmath> //sqrt()\pow()\abs()\ceil()\floor()\max()\min() using namespace std; int main(){ double a,b; cin>>a>>b; printf("%.2lf\n",a-(int)(a/b)*b); /* int c; c=a/b; double d; d=a-c*b; printf("%.2lf\n",d); */ return 0; }