#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  vector<int> g;
  g.resize(n);
  int a;
  for (int(i) = 0; i < int(n); ++i) {
    cin >> a;
    g[i] = a;
  }
  int mn = abs(g[0] - g[n - 1]);
  int f = 1, s = n;
  for (int i = 0; i < n - 1; i++) {
    if (abs((g[i + 1] - g[i])) < mn) {
      mn = abs(g[i + 1] - g[i]);
      f = i + 2;
      s = i + 1;
    }
  }
  cout << f << " " << s;
}
