#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(){ int a,b,c; cin>>a>>b; c=(a-b)%b; if(a%b==0) { cout<<(a-c)%b<<b-c<<endl; } else { cout<<a%b<<endl; } return 0; }