for chat

load Libraries

## Warning: package 'Scale' was built under R version 3.4.4

## Warning: package 'ggthemes' was built under R version 3.4.4

## Warning: Removed 23 rows containing non-finite values (stat_count).

## Warning: Removed 23 rows containing non-finite values (stat_count).

## Warning: Removed 23 rows containing non-finite values (stat_count).