#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  int n;
  cin >> n;
  int a[n];
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  int min = abs(a[1] - a[n]), l = n, r = 1;
  for (int i = 2; i <= n; i++) {
    if (abs(a[i] - a[i - 1]) < min) {
      min = abs(a[i] - a[i - 1]);
      l = i - 1;
      r = i;
    }
  }
  cout << l << " " << r;
  return 0;
}
