import sequtils,strutils,math

var
    S = stdin.readline
    i1,i2 : int
    ans = high(int)

for s in 1..S.len:
    if S[^s] == 'w':
        if i1 == 0:
            i1 = s
        elif i2 == 0:
            i2 = s
        else:
            i1 = i2
            i2 = s
    elif S[^s] == 'c':
        if i2 != 0:
            ans = min(s - i1 + 1,ans)
if ans != high(int):
    echo ans
else:
    echo -1