how many people were diagnosed with speech disturbance nec after the previous diagnosis of fx surg nck humerus-clos within 2 months?
select count( distinct t1.subject_id ) from ( select admissions.subject_id, diagnoses_icd.charttime from diagnoses_icd join admissions on diagnoses_icd.hadm_id = admissions.hadm_id where diagnoses_icd.icd9_code = ( select d_icd_diagnoses.icd9_code from d_icd_diagnoses where d_icd_diagnoses.short_title = 'speech disturbance nec' ) ) as t1 join ( select admissions.subject_id, diagnoses_icd.charttime from diagnoses_icd join admissions on diagnoses_icd.hadm_id = admissions.hadm_id where diagnoses_icd.icd9_code = ( select d_icd_diagnoses.icd9_code from d_icd_diagnoses where d_icd_diagnoses.short_title = 'fx surg nck humerus-clos' ) ) as t2 on t1.subject_id = t2.subject_id where t1.charttime < t2.charttime and datetime(t2.charttime) between datetime(t1.charttime) and datetime(t1.charttime,'+2 month')