import std.stdio,
       std.conv,
       std.string,
       std.range,
       std.math,
       std.algorithm;

void main()
{
    auto N = readln.strip.to!int;
    auto X = readln.split.to!(int[]);

    auto x = X.sort.uniq.array;
    (x.length < 2 ? 0 : 1000001.reduce!((a,b) => min(a,x[b]-x[b-1]))(1.iota(x.length))).writeln;
}