class Solution {
public:
    /**
     * the number of 0
     * @param n long长整型 the number
     * @return long长整型
     */
    long long thenumberof0(long long n) {
        // write code here
        if( n < 5) {
            return 0;
        }
        return n / 5 + thenumberof0(n / 5);
    }
};