#include<bits/stdc++.h>
#include<atcoder/all>
using namespace atcoder;
using namespace std;
using ll=long long;
const int m=32;
ll gcd(ll x,ll y){
  if(y==0)return x;
  else return gcd(y,x%y);
}
int main(){
	int a,b;
	cin>>a>>b;
	b=abs(b);
	a+=b*1000;
	cout<<a%b<<endl;
}