Your buttons are declared as INPUT inside setup(). This configuration demands that pull-up or pull-down resistors be installed with the buttons. Are those resistors installed? It is much more common (and easier) to use the internal pullup resistors on the arduino. Declare the pin as INPUT_PULLUP, wire one side of the button to ground and the other to the pin. When pressed, it will read LOW, when not pressed, it will read HIGH.
You should also check out the state change detection example in the IDE (File->examples->02.digital->State Change Detection) to learn how to know when you button gets pressed, not if it is currently pressed.