AWSTemplateFormatVersion: "2010-09-09"  
Parameters:
  LatestAmiId:
    Type: 'AWS::SSM::Parameter::Value<AWS::EC2::Image::Id>'
    Default: '/aws/service/ami-amazon-linux-latest/amzn2-ami-hvm-x86_64-gp2'
Resources:  
  WebInstance:
    Type: AWS::EC2::Instance
    Properties:
      InstanceType: t2.nano
      ImageId: !Ref LatestAmiId
      SecurityGroupIds: [ !ImportValue SCDemoSG ]
      SubnetId: !Select [ 0, !Split [ ",", !ImportValue SCDemoPublicSubnet ] ]