#include <iostream>
#include <set>
#include <algorithm>
using namespace std;
int cnt_all[6001], cnt_after_last_zero[6000];
int main()
{
    memset(cnt_all, 0, sizeof cnt_all);
    memset(cnt_after_last_zero, 0, sizeof cnt_after_last_zero);
    bool dali = false;
    while(true) {
        int x;
        cin >> x;
        if(x == 11111) break;
        if(x == 0 and dali) {
            memset(cnt_after_last_zero, 0, sizeof cnt_after_last_zero);
        }
        if(x == 0) {
            dali = true;
        }
        if(x != 0 and dali) {
            cnt_all[x]++;
            cnt_after_last_zero[x]++;
        }
    }
    int maks = -1, minn = 6005;
    for(int i = 6000; i >= 600; i--) {
        cnt_all[i] -= cnt_after_last_zero[i];
        if(cnt_all[i] > 0) {
            maks = max(maks, i);
            minn = min(minn, i);
        }
    }
    cout << maks - minn << endl;
    return 0;
}