# -*- coding: utf-8 -*-
import random

def rev(N):
    s = str(N)
    s = s[::-1]
    return int(s)

if __name__ == '__main__':
    P, Q, x, y = map(int, input().split())
    while True:
        k = random.randint(0, 10**12)
        N = k * Q + y
        if N % 10 == 0:
            continue
        if rev(N) % P == x:
            ans = rev(N)
            break
    print(ans)