import std.stdio, std.string, std.conv;
import std.algorithm, std.array;
import core.stdc.stdlib;

void main(){
    auto s = readln.strip.to!int;
    int[] arr = readln.strip.split.map!(to!int).array;
    if(s == 1){0.writeln;exit(-1);}
    arr.sort;
    int ans = int.max, before;
    foreach(i, x; arr){
        if(i == 0) continue;
        if(ans > arr[i] - before){
            ans = arr[i] - before;
        }
        before = arr[i];
    }
    writeln(ans != 0 ? ans : 1);
}