S = input()

if 'c' in S:
    X = S.index('c')
else:
    print(-1)
    exit()

if 'w' in S[X+1:]:
    Y = S[X+1:].index('w')
else:
    print(-11)
    exit()

if 'w' in S[X+Y+2:]:
    Z = S[X+Y+2:].index('w')
else:
    print(-111)
    exit()

print(X+Y+Z+3 - (X+1) + 1)