Active galactic nuclei (AGNs) show a correlation between the size of the broad line region (BLR) and the monochromatic continuum luminosity at 5100 AA, allowing black hole mass estimation based on single-epoch spectra. However, the validity of the correlation is yet to be clearly tested for high-luminosity AGNs. We present the first reverberation-mapping results of the Seoul National University AGN monitoring program (SAMP), which is designed to focus on luminous AGNs for probing the high end of the size-luminosity relation. We report time lag measurements of two AGNs, namely, 2MASS J10261389+5237510 and SDSS J161911.24+501109.2, using the light curves obtained over a $sim$1000 day period with an average cadence of $sim$10 and $sim$20 days, respectively for photometry and spectroscopy monitoring. Based on a cross-correlation analysis and H$beta$ line width measurements, we determine the H$beta$ lag as $41.8^{+4.9}_{-6.0}$ and $52.6^{+17.6}_{-14.7}$ days in the observed-frame, and black hole mass as $3.65^{+0.49}_{-0.57} times 10^7 M_{odot}$ and $23.02^{+7.81}_{-6.56} times 10^7 M_{odot}$, respectively for 2MASS J1026 and SDSS J1619.