#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, minn = 1003, index = 0;
  cin >> n;
  vector<int> v(n);
  for (int i = 0; i < n; i++) {
    cin >> v[i];
    if (i != 0) {
      if (minn > (abs(v[i] - v[i - 1]))) {
        minn = abs(v[i] - v[i - 1]);
        index = i;
      }
    }
  }
  if (minn >= (abs(v[0] - v[n - 1]))) {
    cout << 1 << ' ' << n << endl;
    return 0;
  }
  cout << index << ' ' << index + 1 << endl;
  return 0;
}
