#include <bits/stdc++.h>
using namespace std;
int main() {
  int n;
  cin >> n;
  int a[101], min = 1500, r1, r2;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  min = abs(a[1] - a[n]);
  r1 = n;
  r2 = 1;
  for (int i = 1; i < n; i++) {
    if ((abs(a[i] - a[i + 1])) < min) {
      min = abs(a[i] - a[i + 1]);
      r1 = i;
      r2 = i + 1;
    }
  }
  cout << r1 << " " << r2;
}
