#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, c, b, d;
  cin >> n;
  int a[n];
  for (int i = 0; i <= n - 1; i++) cin >> a[i];
  int min = abs(a[0] - a[n - 1]);
  b = 1;
  d = n;
  for (int i = 0; i <= n - 2; i++) {
    c = abs(a[i + 1] - a[i]);
    if (min > c) {
      min = c;
      b = i + 1;
      d = i + 2;
    }
  }
  cout << b << " " << d;
}
