s = input()
idx_c = []
idx_w = []
l = 10**5
for i, x in enumerate(s):
    if x == "c":
        idx_c.append(i)
    if x == "w":
        idx_w.append(i)
for ci in idx_c:
    for i in range(len(idx_w)-1):
        if ci < idx_w[i]:
            l = min(l, idx_w[i+1] - ci + 1)
if l == 10**5:
    print(-1)
else:
    print(l)