---
AWSTemplateFormatVersion: "2010-09-09"
Description: >
  Test Good Sub Strings
Mappings:
  myMap:
    us-east-1:
      32: ami-1234567
      64: ami-abcdefg
Resources:
  myInstance1:
    Type: AWS::EC2::Instance
    Properties:
      ImageId: !FindInMap [ !FindInMap [ myMap, !Ref 'AWS::Region', !Ref 'AWS::Region' ], !Ref 'AWS::Region', 32 ]
  myInstance2:
    Type: AWS::EC2::Instance
    Properties:
      ImageId:
        Fn::FindInMap:
        - !FindInMap [ myMap, !Ref 'AWS::Region', !Ref 'AWS::Region'  ]
        - !FindInMap [ myMap, !Ref 'AWS::Region', !Ref 'AWS::Region'  ]
        - !FindInMap [ myMap, !Ref 'AWS::Region', !Ref 'AWS::Region'  ]
  myInstance3:
    Type: AWS::EC2::Instance
    Properties:
      ImageId:
        Fn::FindInMap:
        - !Ref myInstance1
        - !Ref myInstance1
        - !Ref myInstance1