#include <cstdio>
#include <algorithm>

using std::max;

const int NX = 1001;

int N;
int A[ NX ];

int main()
{
  int sol = 0;
  int start;

  scanf( "%d", &N );
  for( int i = 0; i < N; ++i )
  {
    scanf( "%d", A+i );

    if( !i )
    {
      start = A[i];
      continue;
    }

    if( A[i] > A[i-1] )
      sol = max( sol, A[i] - start );
    else
      start = A[i];
  }

  printf( "%d\n", sol );
}