Number counts of sources detected in the CLASH fields as a function of flux. Left panels: cumulative number counts of the lensed sources in the soft band (upper left) and hard band (lower left). The number counts are compared with the prediction by the model of Gilli et al. (2007) after removing the foreground sources. Right panels: effects of the flux magnification and source dilution shown separately in the soft band (upper right) and hard band (lower right).