n = int(input())
s = input()

idx = 0
right = 0
left = 0
total = 0

while idx < n:
    while idx < n and s[idx] == '>':
        right += 1
        idx += 1
    while idx < n and s[idx] == '<':
        left += 1
        idx += 1
    total += right * left
    left = 0
print(total)