import sys
from collections import Counter

sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1
p2D = lambda x: print(*x, sep="\n")
def MI(): return map(int, sys.stdin.readline().split())
def LI(): return list(map(int, sys.stdin.readline().split()))
def LLI(rows_number): return [LI() for _ in range(rows_number)]

def main():
    s=input()
    pos_c=101
    pos_w=-2
    ans=[]
    for i,c in enumerate(s):
        if c=="c":
            pos_c=i
        if c=="w":
            if pos_w>pos_c:
                ans.append(i-pos_c+1)
                pos_w=-2
            else:
                pos_w=i
    if ans:print(min(ans))
    else:print(-1)


main()