#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, p;
  cin >> n;
  int sum;
  int x[n + 1];
  for (int i = 1; i <= n; i++) {
    cin >> x[i];
  }
  int min = 1001;
  int a, b;
  for (int i = 1; i < n; i++) {
    if (fabs(x[i] - x[i + 1]) < min) {
      min = fabs(x[i] - x[i + 1]);
      a = i, b = i + 1;
    }
  }
  if (fabs(x[n] - x[1]) < min) {
    a = n;
    b = 1;
  }
  cout << a << " " << b << endl;
  return 0;
}
