# -*- coding: utf-8 -*-
if __name__ == '__main__':
    s = input()
    c = sorted([i for i in range(len(s)) if s[i] == "c"])
    w = sorted([i for i in range(len(s)) if s[i] == "w"])
    
    found = []
    for i in c:
        wcount = 0
        for j in w:
            if i < j:
                wcount += 1
                if wcount == 2:
                    found.append(j - i + 1)
                    break
    
    result = -1               
    if len(found) > 0:
        result = min(found)
    print(result)