Shuvo Noboborsho!

The number of unique combinations of choosing a panjabi along with a pajama among $N$ panjabis and $M$ pajamas is $N \times M$. And Pranto needs $S$ seconds to try a combination. Maximum combination Pranto can try within $K$ seconds is $\lfloor \frac{K}{S} \rfloor$$-$the floor integer value of $\frac{K}{S}$. So, the answer is $Minimum( N \times M, \lfloor \frac{K}{S} \rfloor )$.