import java.util.Scanner;
import java.util.ArrayDeque;
class Main{
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		String S = sc.next();
		int[] imos = new int[S.length()+1];
		ArrayDeque<Integer> deq = new ArrayDeque<>();
		ArrayDeque<Integer> subDeq = new ArrayDeque<>();
		int sub = 0;
		for(int i=S.length()-1;i>=0;i--){
			if(S.charAt(i)=='<'){
				Integer index1 = deq.peekLast();
				if(index1!=null&&i+1+sub<index1){
					deq.removeLast();
					imos[i]++;
					imos[index1+1]--;
					sub = index1-i+1;
					sub += subDeq.size()>0?subDeq.pollLast():0;
				}
				else{
					deq = new ArrayDeque<>();
					subDeq = new ArrayDeque<>();
					sub = 0;
				}
			}
			if(S.charAt(i)=='>'){
				deq.addLast(i);
				subDeq.addLast(sub);
				sub = 0;
			}
		}
		int ans = 0;
		for(int i=0;i<S.length();i++){
			imos[i+1] += imos[i];
			ans += Math.max(0,1-imos[i]);
		}
		System.out.println(ans);
	}
}