The ornamental design for a pair of frontdoors, as shown and described.
FIG. 1 is a left side elevation view of a pair of front doors, in use condition showing my new design;
FIG. 2 is an enlarged left side elevation view;
FIG. 3 is a right side elevation view;
FIG. 4 is a rear elevation view thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The dash-dash even broken lines illustrate and surround portions of the pair of front doors that form no part of the claimed design. The dash-dot-dot broken lines shown in the drawings illustrate vehicle environmental subject matter which forms no part of the claimed design.