def ops_cadenes(l, comandes):
    for i in range(len(l)):
        if comandes[i] == 'dup':
            l[i] = l[i]*2
        elif comandes[i] == 'cutf':
            l[i] = l[i][1:]
        elif comandes[i] == 'cute':
            l[i] = l[i][:-1]