#include <stdio.h>

int main(void){
  long n, x, t, m = 100000000;
  scanf("%ld", &n);
  for(; n > 0; n--){
    scanf("%ld", &x);
    if(t - x < m && t - x > 0)
      m = t - x;
    else if(x - t < m && x - t > 0)
      m = x - t;
    t = x;
  }
  if(m == 100000000)
    printf("0\n");
  else
    printf("%ld\n", m);
  return 0;
}