#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, b, k, s, t, min = 100000;
  cin >> n;
  int a[n], w;
  for (int i = 1; i <= n; i++) cin >> a[i];
  for (int i = 1; i <= n; i++) {
    if (i == n) {
      b = abs(a[i] - a[1]);
      if (min > b) {
        min = b;
        t = min;
      }
    } else {
      b = abs(a[i] - a[i + 1]);
      if (min > b) {
        min = b;
        w = min;
        s = i;
      }
    }
    if (i == n) break;
  }
  if (w == min) {
    cout << s << " " << s + 1 << endl;
  } else
    cout << n << " " << 1 << endl;
}
