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