#include <bits/stdc++.h>
using namespace std;
int x[10000];
int main() {
  int n, i, j, mini = 9999999, z, y;
  cin >> n;
  for (i = 1; i <= n; i++) cin >> x[i];
  for (i = 2; i <= n; i++) {
    if (abs(x[i] - x[i - 1]) < mini) {
      mini = abs(x[i] - x[i - 1]);
      z = i;
      y = i - 1;
    }
  }
  if (abs(x[n] - x[1]) < mini)
    cout << n << " " << 1;
  else
    cout << z << " " << y;
}
