#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, minn = 1000000, indx;
  cin >> n;
  int arr[n + 1];
  for (int i = 1; i <= n; i++) cin >> arr[i];
  for (int i = 1; i < n; i++) {
    if (abs(arr[i] - arr[i + 1]) < minn) {
      minn = abs(arr[i] - arr[i + 1]);
      indx = i;
    }
  }
  if (abs(arr[1] - arr[n]) < minn)
    cout << n << " " << 1 << endl;
  else
    cout << indx << " " << indx + 1 << endl;
  return 0;
}
