British astronomer Eddington liked to ride a bike. It is said that in order to show off his skill, he has even defined an "Eddington number", E -- that is, the maximum integer E such that it is for E days that one rides more than E miles. Eddington's own E was 87.

Now given everyday's distances that one rides for N days, you are supposed to find the corresponding E (≤).

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N (≤), the days of continuous riding. Then N non-negative integers are given in the next line, being the riding distances of everyday.

Output Specification:

For each case, print in a line the Eddington number for these N days.

Sample Input:

106 7 6 9 3 10 8 2 7 8

Sample Output:

6

1 #include 
     
       2 #include 
      
        3 #include 
       
         4 using namespace std; 5 int n; 6 int main() 7 { 8     cin >> n; 9     vector
        
         v(n);10     for (int i = 0; i < n; ++i)11         cin >> v[i];12     sort(v.begin(), v.end());13     int k = 0;14     for (k = 0; k < n; ++k)15         if (v[k] > n - k)16             break;17     cout << n - k;18     return 0;19 }