AWSCredentials credentials = new BasicAWSCredentials(accessKey, secretKey);
   AmazonElasticMapReduce emr = new AmazonElasticMapReduceClient(credentials);

HadoopJarStepConfig config = new StreamingStep {
    Inputs = new List<string> { "s3://elasticmapreduce/samples/wordcount/input" },
    Output = "s3://my-bucket/output/",
    Mapper = "s3://elasticmapreduce/samples/wordcount/wordSplitter.py",
    Reducer = "aggregate"
}.ToHadoopJarStepConfig();

StepConfig wordCount = new StepConfig {
    Name = "Word Count",
    ActionOnFailure = "TERMINATE_JOB_FLOW",
    HadoopJarStep = config
};

RunJobFlowRequest request = new RunJobFlowRequest {
    Name = "Word Count",
    Steps = new List<StepConfig> { wordCount },
    LogUri = "s3://log-bucket/",
    Instances = new JobFlowInstancesConfig {
        Ec2KeyName = "keypair",
        HadoopVersion = "0.20",
        InstanceCount = 5,
        KeepJobFlowAliveWhenNoSteps = true,
        MasterInstanceType = "m1.small",
        SlaveInstanceType = "m1.small"
   }
};

   RunJobFlowResult result = emr.RunJobFlow(request).RunJobFlowResult;