#include<stdio.h>
#include<string.h>


FILE *in;
FILE *out;

typedef struct para_typ{
unsigned int x,y;
}PARA;
PARA sold[8001];
char sherenga[10000];
unsigned int count;
int c,p_end;
int /*check=0,*/check2=0;

int main(void)
 {
 in=fopen("input.txt","r");
 out=fopen("output.txt","w");
 fscanf(in,"%s",sherenga);
/* check=0;*/
 while(1) /*check!=1*/
   {
   for(c=0;c<strlen(sherenga);c++)
      {
     if(sherenga[c]=='>' && sherenga[c+1]=='<')
	{
	p_end++;
      sold[p_end].x=c;
      sold[p_end].y=c+1;
       count++;
	}
      }
    if(check2==count)
      {
//      check=1;
      fprintf(out,"%d",count);
 fclose(in);
 fclose(out);
 return 0;
      }

    if(check2!=count)
      {
      for(c=0;c<=p_end;c++)
       {

	  sherenga[sold[c].x]='<';
	  sherenga[sold[c].y]='>';
	}
     check2=count;
       }
     }
 }