#include <sstream>
#include <algorithm>//sort()
#include <vector>
using namespace std;
string s;
vector<int> input;
vector<int> counts;
void serialnum(int n)
{
int count=1;
int i;
for (i=0;i<=n-1;i++)
{
if (input[i+1]!=input[i]+1)
{
counts.push_back(count);
count=1;//连续小序列结束,重新计数
continue;
}
count++;
}
if (count>1 && i==n-1)
{
count++;
}
}
int main()
{
cin>>s;
stringstream ss(s);
char x;
int n;
while(ss>>x)
{
if (x==']')
{
break;
}
ss>>n;
input.push_back(n);
}
sort(input.begin(),input.end());
serialnum(input.size());
int maxlength=1;
for (int i=0;i<counts.size();i++)
{
if (counts[i]>maxlength)
{
maxlength=counts[i];
}
}
cout<<maxlength;
return 0;
}