s = input()

cww = ""
idx = []

for i, v in enumerate(s):
    if v == "c":
        cww += v
        idx.append(i)
    elif v == "w":
        cww += v
        idx.append(i)
              
if len(cww) == 3 and cww == "cww":
    print(idx[2] - idx[0] + 1)
else:
    print(-1)