#include <bits/stdc++.h>
using namespace std;
int main() {
int a,b,c,min=99999999;
vector<int>v;
cin >> a >> b;
while(b--){
cin >> c;
v.push_back(c);
}
sort(v.begin(),v.end());
for(int i=0;i<=v.size()-a;i++){
int z=v[i+a-1]-v[i];
cout << z << endl;
if(z<min){
min=z;
}
}
cout << min << endl;
}
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