//Increments x by one if Button 1 is Low
The comment is incorrect; x is incremented when the pin transitions from LOW to HIGH because of the while loop.
Please use code tags when posting code.
y=5.759; //circumfrence of wheel in feet
z=0; //feet traveled so far
m=5280; // feet per mile
Unless you're planning on changing these values,
const float y=5.759; //circumfrence of wheel in feet
const float m=5280; // feet per mile
when they're declared would be clearer.