【ECJTU_ACM 11级队员2012年暑假训练赛（8） G Nearly Lucky Number】

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ECJTU_ACM 11级队员2012年暑假训练赛（8）
4:30:00
 
 
          
G - Nearly Lucky Number
Time Limit:2000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u

Description

Petya loves lucky numbers. We all know that lucky numbers are the positive integers whose decimal representations contain only the lucky digits 4 and 7. For example, numbers 47, 744, 4 are lucky and 5, 17, 467 are not.

Unfortunately, not all numbers are lucky. Petya calls a number nearly lucky if the number of lucky digits in it is a lucky number. He wonders whether number n is a nearly lucky number.

Input

The only line contains an integer n (1 ≤ n ≤ 1018).

Please do not use the %lld specificator to read or write 64-bit numbers in С++. It is preferred to use the cin, cout streams or the %I64d specificator.

Output

Print on the single line "YES" if n is a nearly lucky number. Otherwise, print "NO" (without the quotes).

Sample Input

Input
40047
Output
NO
Input
7747774
Output
YES
Input
1000000000000000000
Output
NO

Hint

In the first sample there are 3 lucky digits (first one and last two), so the answer is "NO".

In the second sample there are 7 lucky digits, 7 is lucky number, so the answer is "YES".

In the third sample there are no lucky digits, so the answer is "NO".

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Anything about the OJ, please ask in the forum, or contact author:Isun
Server Time: 2012-08-13 10:52:34
 1 // Project name : G
 2 // File name    : main.cpp
 3 // Author       : iCoding
 4 // E-mail       : honi.linux@gmail.com
 5 // Date & Time  : Fri Aug 10 15:24:28 2012
 6 
 7 
 8 #include <iostream>
 9 #include <stdio.h>
10 #include <string>
11 #include <cmath>
12 #include <algorithm>
13 using namespace std;
14 
15 /*************************************************************************************/
16 /* data */
17 
18 
19 /*************************************************************************************/
20 /* procedure */
21 
22 
23 /*************************************************************************************/
24 /* main */
25 int main()
26 {
27     string s;
28     while (cin >> s)
29     {
30         int count = 0;
31         int top = s.length() - 1;
32         for (int i = 0; i <= top; i++)
33         {
34             if (s[i] == '4' || s[i] == '7')
35             {
36                 count++;
37             }
38         }
39 
40         //cout << count << endl;
41 
42         bool yes = true;
43         if (count == 0)
44         {
45             yes = false;
46         }
47         while (yes == true && count)
48         {
49             if (count % 10 == 4 || count % 10 == 7)
50             {
51                 count /= 10;
52             }
53             else
54             {
55                 yes = false;
56             }
57         }
58 
59         if (yes)
60         {
61             cout << "YES" << endl;
62         }
63         else
64         {
65             cout << "NO"  << endl;
66         }
67     }
68     return 0;
69 }
70 
71 // end 
72 // Code by Sublime text 2
73 // iCoding@CodeLab
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原文地址：https://www.cnblogs.com/ismdeep/p/2635983.html