#include<bits/stdc++.h>
using namespace std;
int main()
{
	int b[20]={0},i,m,a[50]={0},n=1;
	for(i=0;i<50;i++){
		cin>>a[i];
		b[a[i]]++;
	}
	for(m=0;m<20;m++){
		if(b[m+1]>b[m])
		swap(b[m+1],b[m]);
	}	
		cout<<b[0];
	return 0;
}
/**************************************************************
	Problem: 1180
	User: houshanglin
	Language: C++
	Result: Wrong Answer
****************************************************************/