import sys

S = input()
# S = "ccwwccw"

cpos = [i for i, x in enumerate(S) if x == "c"]

wpos = [i for i, x in enumerate(S) if x == "w"]

ans = []

if len(cpos) == 0 or len(wpos) <= 1:
    print(-1)
    sys.exit()

for i in cpos:

    wpostemp = [j for j in wpos if j > i]

    if len(wpostemp) <= 1:
        break

    anstemp = wpostemp[1] - i + 1
    ans.append(anstemp)

if not ans:
    print(-1)
else:
    print(min(ans))