import sys
import math
#from collections import deque, defaultdict, Counter
#import heapq
#import bisect
#import itertools
#import functools

# 外部ライブラリ（AtCoder環境で利用可能）
#from sortedcontainers import SortedList, SortedSet, SortedDict
#from atcoder.dsu import DSU
#from atcoder.segtree import SegTree
#from atcoder.lazysegtree import LazySegTree
#from atcoder.fenwicktree import FenwickTree

# 入力高速化
#input = sys.stdin.readline
# 再帰回数上限

# よくあるmod
#MOD = 1000000007
MOD = 998244353

def solve():
    # 解答ここから
    from collections import Counter
    S = input()
    cnt = 0
    for i in range(len(S) - 2):
        s = S[i:i+3]
        if (s[0] == s[1] or s[1] == s[2]) and s[0] != s[2]:
            cnt += 1
        
    print(cnt)
if __name__ == '__main__':
    T = 1
    for _ in range(T):
        solve()