c# - Using Mathf.Clamp causes object to start at lowest limit -

i using mathf.clamp ensure object flying upwards stays within +/- 45 degrees. with:

x = input.acceleration.x; rotationz -= x * sensitivityz; rotationz = mathf.clamp (rotationz, 45f, 120f); transform.eulerangles = new vector3 (transform.eulerangles.x, transform.eulerangles.y, rotationz); 

my object starts @ 90 degree angle, straight up. when run code first forces object lower limit, 45. want stay in center. have accomplished creating variable called addff , when first starts script give value of 45. add addff first value , set 0 after so.

public float addff = 45;    void launch(){ x = input.acceleration.x; rotationz -= x * sensitivityz; rotationz = mathf.clamp (rotationz, 45f + addff, 120f); addff = 0; transform.eulerangles = new vector3 (transform.eulerangles.x, transform.eulerangles.y, rotationz);  } 

so, adds variable total making 90 when first runs. when ran again set 0 sets 45. want to, keep object facing 90 degrees, when start there cleaner way of doing this?