Matlab script error: please help me to check and correct it

I wrote a MATLAB script to ask users to choose one of the shape and calculate the area of the shape.

My script is as follows. I can run with circle and square, but others cannot. I think it's the number of alphabet problem.

Any method to solve this??

fprintf('Choose one of the following to find the area: \n 1. circle \n 2. square \n 3. trapezium \n 4. triangle \n 5. rectangle \n');

s=input('Please choose one of the shape: ', 's');

if s=='circle'

r=input('Enter the radius of the circle(cm):');

area=(4/3)*pi*r;

fprintf('The area of the circle is %.4f cm^2. \n', area);

elseif s=='square'

a=input('Enter the length of one side(cm): ');

area=a*a;

fprintf('The area of square is %.4fcm^2. \n', area);

elseif s=='trapezium'

a=input('Enter the length of the first parallel side(cm): ');

b=input('Enter the length of another parallel side(cm): ');

h=input('Enter the perpendicular distance between the pair of parallel sides(cm): ');

area=0.5*(a+b)*h;

fprintf('The area of trapezium is %.4fcm^2. \n', area);

elseif s=='triangle'

b=input('Enter the length of the base(cm): ');

h=input('Enter the length of the height(cm): ');

area=0.5*h*b;

fprintf('The area of triangle is %.4fcm^2. \n', area);

elseif s=='rectangle'

a=input('Enter the length of one side(cm): ');

b=input('Enter the length of another side(cm): ');

area=a*b;

fprintf('The area of rectangle is %.4fcm^2. \n', area);

else

disp('Please choose again.');

end