#include <iostream>
#include <algorithm>
#include <iomanip>
#include <vector>
#include <queue>
#include <deque>
#include <set>
#include <map>
#include <tuple>
#include <cmath>
#include <numeric>
#include <functional>
#include <cassert>

#define debug_value(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << #x << "=" << x << endl;
#define debug(x) cerr << "line" << __LINE__ << ":<" << __func__ << ">:" << x << endl;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }

using namespace std;
typedef long long ll;

template<typename T>
vector<vector<T>> vec2d(int n, int m, T v){
    return vector<vector<T>>(n, vector<T>(m, v));
}

template<typename T>
vector<vector<vector<T>>> vec3d(int n, int m, int k, T v){
    return vector<vector<vector<T>>>(n, vector<vector<T>>(m, vector<T>(k, v)));
}

template<typename T>
void print_vector(vector<T> v, char delimiter=' '){
    if(v.empty()) {
        cout << endl;
        return;
    }
    for(int i = 0; i+1 < v.size(); i++) cout << v[i] << delimiter;
    cout << v.back() << endl;
}

void test(){
    int p = 90007;
    int r = 10;
    set<int> st;
    int cur = 1;
    while(true){
        if(st.count(cur)) break;
        st.insert(cur);
        cur *= 10;
        cur %= p;
    }
    debug_value(st.size())
}

ll f(string s, ll p){
    ll ans = 0;
    for(int i = 0; i < s.size(); i++){
        ans *= 10;
        ans += s[i]-'0';
        ans %= p;
    }
    return ans;
}

int main(){
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout << setprecision(10) << fixed;
    ll p, q, x, y; cin >> p >> q >> x >> y;
    while(y%10 == 0) y += q;
    auto s = to_string(y);
    auto ans = s;
    reverse(ans.begin(), ans.end());
    ll cur = stoll(ans);
    if(cur%p == 0){
        y += q;
        while(y%10 == 0) y += q;
        auto s = to_string(y);
        ans = s;
        reverse(ans.begin(), ans.end());
        cur = stoll(ans);
    }
    while(cur%p != x){
        cur *= 10;
        cur %= p;
        ans += '0';
    }
    cout << ans << endl;
    assert(f(ans, p) == x);
    reverse(ans.begin(), ans.end());
    assert(f(ans, q) == y%q);
}