19 lines
473 B
Java
19 lines
473 B
Java
import java.util.*;
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public class nearlyLuckyNumberCF {
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public static void main(String args[]){
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Scanner in = new Scanner(System.in);
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long n = in.nextLong();
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int count = 0;
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while(n > 0){
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if(n % 10 == 4 || n % 10 == 7){
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count++;
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}
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n = n/10;
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}
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if(count == 7 || count == 4)
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System.out.print("YES");
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else
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System.out.print("NO");
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}
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}
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