백준 6064 파이썬

for k in range(int(input())):

    M,N,x,y = map(int,input().split(" "))

    num=-1

    i=0

    while y!= ((M*i) + x) %N:

        i=i+1

        if i>N:

            break

    Y = M *i +x

    if Y > M*N:

        print(-1)

    else:

        print(Y)