#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;
}