protected void reduce(Text key,Iterable<IntWritable> values,Context context) throws IOException, InterruptedException {
		StringBuffer sb = new StringBuffer();
		sb.append("[");
		for(IntWritable it :values){
			sb.append(it);
			sb.append("_");
		}
		sb.append("]");
		context.write(key, new Text(sb.toString()));
	}