The ornamental design for a displayscreen with a graphical user interface, as shown and described.
FIG. 1 is a first image in the sequence for an animated image of a display screen with a graphical user interface showing my new design;
FIG. 2 is a second image thereof; and,
FIG. 3 is a third image thereof.
The appearance of the animated image sequentially transitions between the images shown in FIGS. 1-3. The process or period in which one image transitions to another forms no part of the claimed design.
The outermost broken-line perimeter illustrates a display screen or portion thereof and forms no part of the claimed design. The remaining broken lines illustrate portions of a graphical user interface and form no part of the claimed design.