FIR Low Pass Filter using inbuilt MATLAB function

%equiripple FIR filter
Fs=1000;
Fp=input('Input the pass band frequency Fp= ');
Fst=input('Input the stop band frequency Fst= ');
Ap=input('Input the pass band attenuation Ap= ');
Ast=input('Input the stop band attenuation Ast= ');
d=fdesign.lowpass('Fp,Fst,Ap,Ast');
Hd=design(d,'equiripple');
fvtool(Hd);