#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  long long arr[1001];
  int n;
  cin >> n;
  for (int i = 0; i < n; cin >> arr[i++])
    ;
  int mini = 100000;
  int ind1, ind2;
  for (int i = 0; i < n - 1; i++) {
    if (abs(arr[i] - arr[i + 1]) < mini) {
      mini = abs(arr[i] - arr[i + 1]);
      ind1 = i;
      ind2 = i + 1;
    }
  }
  if (abs(arr[0] - arr[n - 1]) < mini) {
    ind1 = 0;
    ind2 = n - 1;
  }
  cout << ind1 + 1 << " " << ind2 + 1 << endl;
  return 0;
}
