step_map = {'U': 1, 'D': -1}

def count_valleys(step_list):
    counts = {"mountains": 0, "valleys": 0}
    level = 0
    status = ""
    for step in step_list:
        level += step_map[step]
        if step == 'D' and level < 0:
            # we're in a valley
            status = "valley"
        elif step == 'U' and status == "valley" and level == 0:
            counts["valleys"] += 1
            status = ""
    return counts["valleys"]

length = raw_input().strip()
print(count_valleys(list(raw_input().strip())))