import java.util.Scanner; public class Main6 { public static void main(String[] args){ Scanner in = new Scanner(System.in); while(in.hasNext()){ char[] cs = in.nextLine().toCharArray(); int n = cs.length; System.out.println(minPaint(cs, 0, n-1)); } } static int minPaint(char[] cs ,Integer start,int end){ int left = 0; int right = 0; int minLeft = 0; int minRight = 0; while(cs[start]=='R'&&start<end){ start++; } while(cs[end]=='G'&&end>start){ end--; } if(start>=end){ return 0; } while(cs[start+left]=='G'){ left++; } minLeft = left+minPaint(cs, start+left,end); while(cs[end-right]=='R'){ right++; } minRight = right+minPaint(cs, start, end-right); return Math.min(minLeft, minRight); } }