def f_wc(word):
    code= ''
    for lttr in word:
        code+= d_ln[lttr]
    return code
# vagy
    return ''.join([d_ln[lttr] for lttr in word]) 

keys= 'abcdefghijklmnopqrstuvwxyz'
vals= '22233344455566677778889999'
d_ln= {}
for i in range(len(keys)):
    d_ln[keys[i]]= vals[i]