#include <bits/stdc++.h>

using namespace std;
ifstream fin("next.in");
ofstream fout("next.out");

const int base = 10;
using hint = int;
class HugeN {
private:
    bool sign;
    vector <hint> v;
    int cmp(const HugeN& other) {
        if(v.size() != other.v.size()) return v.size() < other.v.size() ? 1 : -1;
        int k = v.size();
        while(k && v[k - 1] == other.v[k - 1]) k--;
        if(k == 0) return 0;
        return v[k - 1] < other.v[k - 1] ? 1 : -1;
    }
public:
    HugeN(hint x = 0) : sign(false) {
        if(x < 0) sign = true, x = -x;
        do {
            v.push_back(x % base);
            x /= base;
        } while(x);
    }
    HugeN(vector <hint> _v, bool _sign = false) : v(_v), sign(_sign) {}
    friend istream& operator >>(istream& in, HugeN& a) {string s; in >> s; if(s[0] == '-') a.sign = true, s.erase(s.begin()); int len = s.length(); a.v.resize(len); for(int i = 0; i < len; i++) a.v[len - 1 - i] = s[i] - '0'; return in;}
    friend ostream& operator <<(ostream& out, const HugeN& a) {if(a.sign) out << "-"; for(int i = a.v.size() - 1; i >= 0; i--) out << a.v[i]; return out;}
    inline bool operator <(const HugeN& other) {return cmp(other) == 1;}
    inline bool operator >=(const HugeN& other) {return cmp(other) <= 0;}
    inline bool operator >(const HugeN& other) {return cmp(other) == -1;}
    inline bool operator <=(const HugeN& other) {return cmp(other) >= 0;}
    HugeN operator +(const HugeN& other) {
        bool s = sign & other.sign;
        if(sign != other.sign) {
            sign ^= 1;
            HugeN c = (*this) - other;
            c.sign ^= 1;
            sign ^= 1;
            return c;
        }
        vector <hint> c(max(v.size(), other.v.size()));
        int i, carry, k = min(v.size(), other.v.size()), kk = c.size();
        for(i = 0, carry = 0; i < k; i++)
            c[i] = (v[i] + other.v[i] + carry) % base,
            carry = (v[i] + other.v[i] + carry) / base;
        if(v.size() > k)
            for(i = k; i < kk; i++)
                c[i] = (v[i] + carry) % base,
                carry = (v[i] + carry) / base;
        else for(i = k; i < kk; i++)
                c[i] = (other.v[i] + carry) % base,
                carry = (other.v[i] + carry) / base;
        if(carry)
            c.push_back(carry);
        return HugeN(c, s);
    }
    HugeN operator +=(const HugeN& other) { return *this = *this + other; }
    HugeN operator -(const HugeN& other) {
        bool s = sign & other.sign;
        if(sign != other.sign) {
            sign ^= 1;
            HugeN c = (*this) + other;
            c.sign ^= 1;
            sign ^= 1;
            return c;
        }
        vector <hint> c(max(v.size(), other.v.size()));
        int i, complement, k = min(v.size(), other.v.size()), kk = c.size();
        if(*this >= other) {
            for(i = 0, complement = 0; i < k; i++)
                if(v[i] - complement < other.v[i]) c[i] = v[i] - complement - other.v[i] + base, complement = 1;
                else c[i] = v[i] - complement - other.v[i], complement = 0;
            if(v.size() > k) for(i = k; i < kk; i++)
                c[i] = v[i] - complement, complement = 0;
            else for(i = k; i < kk; i++)
                c[i] = - complement - other.v[i] + base, complement = 1;
        } else {
            s ^= 1;
            for(i = 0, complement = 0; i < k; i++)
                if(other.v[i] - complement < v[i]) c[i] = other.v[i] - complement - v[i] + base, complement = 1;
                else c[i] = other.v[i] - complement - v[i], complement = 0;
            if(other.v.size() > k) for(i = k; i < kk; i++)
                c[i] = other.v[i] - complement, complement = 0;
            else for(i = k; i < kk; i++)
                c[i] = - complement - v[i] + base, complement = 1;
        }
        if(complement) s ^= 1;
        while(kk > 1 && c[k - 1] == 0) kk--;
        c.resize(kk);
        return HugeN(c, s);
    }
    HugeN operator -=(const HugeN& other) { return *this = *this - other; }
    HugeN operator *(long long x) {
        if(x == 0) return 0;
        bool s = sign ^ (x < 0);
        if(x < 0) x = -x;
        long long carry = 0, k = v.size(); vector <hint> p(k);
        for(int i = 0; i < k; i++)
            carry += x * v[i],
            p[i] = carry % base,
            carry /= base;
        while(carry)
            p.push_back(carry % base),
            carry /= base;
        return HugeN(p, s);
    }
    long long operator %(long long d) {
        long long r = 0;
        for(int i = v.size() - 1; i >= 0; i--)
            r = r * base + v[i],
            r %= d;
        return sign ? -r : r;
    }
};

int main()
{
    HugeN a; long long b;
    fin >> a >> b;
    long long c = a % b;
    //cout << c << " " << a;
    if(c) a += HugeN(b - c);
    fout << a;
    return 0;
}