PROGRAM MAIN
    IMPLICIT NONE
    INTEGER(kind=8) :: T, N, M, A, B, C, D, X, I, ANS, ANSMAX

    READ(*,*) T
    DO I = 1, T
        ANSMAX = 0
        READ(*,*) N, M, A, B, C, D
        DO X = 0, N - 1
            ANS = A * X + B * FLOOR((C * X + D) / DBLE(M))
            IF (ANS > ANSMAX) ANSMAX = ANS
        END DO
        PRINT("(I0)"), ANSMAX
    END DO
END PROGRAM MAIN