#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
 
int main() {
     pair<int, int> nr[100001];
    int mx = 0;
    ifstream fin("distanta.in");
    ofstream fout("distanta.out");
    int n = 0;
    while(cin >> nr[n].first) {
         nr[n++].second = n;
    }
    sort(nr, nr + 1);
    for(int i = 0; i < n; i++) {
        int j = i + 1;
        while(nr[i].first == nr[j].first) {
             mx = max(mx, nr[j].second - nr[i].second);
            j++;
        }
    }
    cout << mx;
}
 

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