#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, m[101], i, min, i1, i2;
  cin >> n;
  for (i = 0; i < n; ++i) cin >> m[i];
  min = abs(m[n - 1] - m[0]);
  i1 = n - 1;
  i2 = 0;
  for (i = 1; i < n; ++i)
    if (abs(m[i] - m[i - 1]) < min) {
      min = abs(m[i] - m[i - 1]);
      i1 = i;
      i2 = i - 1;
    }
  cout << i1 + 1 << " " << i2 + 1;
}
