#include <bits/stdc++.h>
using namespace std;
int main() {
  int a[101];
  int n, m, c = 0, i, j, min = 1000000, id;
  cin >> n;
  for (i = 0; i < n; i++) {
    cin >> a[i];
    if (i == 0) continue;
    if (i > 0) {
      m = abs(a[i - 1] - a[i]);
    }
    if (m < min) {
      min = m;
      id = i;
    }
  }
  m = abs(a[0] - a[n - 1]);
  if (m < min) {
    cout << n << " " << 1;
    return 0;
  }
  cout << id << " " << id + 1;
}
