#include<stdio.h>
char s[500005];
char t[500005];
int b[500005];
int main()
{
	scanf("%s", s);
	int n;
	for (n = 0; s[n] != '\0'; n++);
	int tt = 0, i;
	for (i = 0; i < n; i++)
	{
		if (tt == 0)
		{
			t[tt] = s[i];
			if (s[i] == '<')
				b[tt] = tt;
			else
				b[tt] = -1;	
			tt++;
		}
		else
		{
			if (s[i] == '<')
			{
				t[tt] = '<';
				b[tt] = tt;
				tt++;
			}
			else if (s[i] == '>')
			{
				if (b[tt - 1] < 0 || b[tt - 1] == tt - 1)
				{
					t[tt] = '>';
					b[tt] = -1;
					tt++;
				}
				else
				{
					tt = b[tt - 1];
				}
			}
			else
			{
				t[tt] = '=';
				b[tt] = b[tt - 1];
				tt++;
			}
		}
	}
	printf("%lld\n", tt);
	return 0;
}