Interval probability from a mixed distribution function

The distribution function of a random variable $X$ is given by

$$F(x)=\begin{cases}0, & x<0,\ \frac14, & 0\le x<\frac14,\ \frac12, & \frac14\le x<\frac12,\ \frac34, & \frac12\le x<\frac34,\ \frac{x+3}5, & \frac34\le x<2,\ 1, & x\ge2.\end{cases}$$

Then $P\left(\frac14\le X\le1\right)$ is