def FIND(S):
    min_length = float('inf')
    first_c = -1
    first_w = -1
    for i, char in enumerate(S):
        if char == 'c':
            first_c = i
        elif char == 'w':
            if first_c != -1:
                if first_w == -1:
                    first_w = i
                else:
                    min_length = min(min_length, i - first_c + 1)
                    first_c = i - 1
                    first_w = i
    return min_length if min_length != float('inf') else -1
print(FIND(input()))