#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n;
  cin >> n;
  vector<int> v(n);
  for (auto &i : v) cin >> i;
  int a = 1, b = n, mn = abs(v[0] - v[v.size() - 1]);
  for (int i = 0; i < n - 1; i++) {
    if (abs(v[i] - v[i + 1]) < mn)
      mn = abs(v[i] - v[i + 1]), a = i + 1, b = i + 2;
  }
  cout << a << " " << b;
}
