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