#include <vector>
#include <algorithm>
using namespace std;
int main(){
    int n;
    cin>>n;
    vector<int>strengths(n);
    for (int i=0;i<n;i++){
        cin>>strengths[i];
    }
    sort(strengths.begin(),strengths.end());
    vector<int>lengths;
    int start=0;
    int strengths_length = 1;
    for (int i=1;i<n;i++){
        if (strengths[i]-strengths[i-1]==1){
            strengths_length++;
        }
		else{
            lengths.push_back(strengths_length);
            start=i;
            strengths_length=1;
        }
    }
    lengths.push_back(strengths_length);
    int min_size=*min_element(lengths.begin(),lengths.end());
    cout<<min_size;
    return 0;
}