#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
using i64 = long long;
using u64 = unsigned long long;
using i32 = int;
using u32 = unsigned int;
#define rep(i,n) for(int i=0; i<(n); i++)


u64 rev_int(u64 x){
    string a = to_string(x);
    reverse(a.begin(), a.end());
    u64 ans = 0;
    for(auto c : a) ans = ans * 10 + (c - '0');
    return ans;
}


int main() {
    u64 P,Q,x,y; cin >> P >> Q >> x >> y;

    for(u64 i=1; i<10000000; i++){
        u64 revans = Q * i + y;
        if(revans % 10 == 0) continue;
        if(rev_int(revans) % P != x) continue;
        cout << rev_int(revans) << endl;
        return 0;
    }
    return 0;
}



struct ios_do_not_sync{
    ios_do_not_sync(){
        std::ios::sync_with_stdio(false);
        std::cin.tie(nullptr);
    }
} ios_do_not_sync_instance;