#include // #include "bits/stdc++.h" #define pout(n) printf ("%d\n", n) #define rep(i,a,n) for (int i = a;i < n;i++) #define per(i,n,a) for (int i = n-1;i >= a;i--) const int d4x[4] = {1, 0, -1, 0}; const int d4y[4] = {0, 1, 0, -1}; const int d8x[8] = { 1,1,0,-1,-1,-1,0,1 }; const int d8y[8] = { 0,1,1,1,0,-1,-1,-1 }; typedef long long ll; using namespace std; int main() { int n; cin >> n; ll x[n]; rep(i,0,n){ cin >> x[i]; } sort(x,x+n); ll ans = 1000000; rep(i,0,n-1){ if(x[i] == x[i+1]) continue; ans = min(ans,x[i+1]-x[i]); } if(0 < ans && ans <= 30) ans = 0; printf("%lld\n",ans); return 0; }