S = input()
st = []
for c in S:
    match c:
        case '<':
            st.append((c, 1))
        case '=':
            if st and st[-1][0] == '=':
                _, cnt = st.pop()
                st.append((c, cnt+1))
            else:
                st.append((c, 1))
        case '>':
            if len(st) >= 2 and st[-2][0] == '<' and st[-1][0] == '=':
                st.pop()
                st.pop()
            else:
                st.append((c, 1))

print(sum(cnt for _, cnt in st))