s=input().split('c')
l=['_'.join(s[x+1:])for x in range(len(s)-1)]
m=100
for i in l:
 w=0
 for j,k in enumerate(i):
  if k=='w':
   w+=1
   if w==2:m=min(m,j+2)
print(-1 if m>99 else m)