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