While loop has disagreeing matrix dimensions

Problematic code:

inputMaterial=input('Enter Tuning Fork Material:')
materialValidation=0;
InputError=1;
while inputMaterial == 'steel' | inputMaterial == 'Steel'
    materialValidation=materialValidation-1;
    InputError=0;
    fprintf('Choice of material: %d','forkMaterial') 
    break
end

Output:

inputMaterial =

'aluminum'

Matrix dimensions must agree.

Error in PP_SUM22 (line 4)

while inputMaterial == 'steel' | inputMaterial == 'Steel'

Answer 1

[Matt J]

while strcmpi(inputMaterial,'steel')

[Craig Johnson]

thanks