import sys

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_w = []
    ans = []
    for i, c in enumerate(s[::-1]):
        if c == "c" and len(pos_w) > 1:
            ans.append(i - pos_w[-2] + 1)
        if c == "w":
            pos_w.append(i)
    if ans:
        print(min(ans))
    else:
        print(-1)

main()