def checkChiwawaLen(strin,startPos):
    first = strin.find("w",startPos)
    second = strin.find("w",first + 1)
    if first == -1 or second == -1:
        return -1
    else:
        return second - startPos + 1

def getCharPositionList(strin,char):
    startPos = 0
    result = []
    while(True):
        targetPos = strin.find(char,startPos)
        if targetPos == -1:
            break
        result.append(targetPos)
        startPos = targetPos + 1
    return result

#inputLine = "chiwawacchichiwawac"
inputLine = input()

posList = getCharPositionList(inputLine,"c")
result = [s for s in [checkChiwawaLen(inputLine,s) for s in posList] if s != -1]
if len(result) != 0:
    print(min(result))
else:
    print(-1)