import re
 
def main():
    line = input()
    match0 = re.search(r'cw(.*?)w', line)
    match1 = re.search(r'c(.*?)w(.*?)w', line)
    if match0:
        print(len(match0.group(0)))
    elif match1:
        print(len(match1.group(0)))
    else:
        print(-1)
 
if __name__ == '__main__':
    main()