#include <stdio.h>



int *pX = nullptr;
int N = 0;


int GetDiff ( int idx1 , int idx2 );


int main ( void ) {


	scanf ( "%d" , &N );


	pX = new int [ N ];
	int diff , diffbuf;

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


	for ( int i = 0; i < ( N - 1 ); i++ ) {

		if ( i == 0 ) {

			diff = GetDiff ( i , i + 1 );

		} else {
			diffbuf = GetDiff ( i , i + 1 );
			if ( diffbuf < diff ) diff = diffbuf;
		}
	}
	delete []pX;


	printf ( "%d\n" , diff );
	return 0;
}

int GetDiff ( int idx1 , int idx2 ) {

	bool bEnableCurrent = false;
	int Current;

	if ( *( pX + idx1 ) != *( pX + idx2 ) ) {
		bEnableCurrent = true;
		Current = *( pX + idx1 ) - *( pX + idx2 );
		if ( Current < 0 ) Current *= -1;
	}

	int diff= -1 , diffbuf;

	for ( int i = idx2 + 1; i < N; i++ ) {
		if ( i == ( idx2 + 1 ) ) {
			diff = GetDiff ( idx1 , i );
		} else {
			diffbuf = GetDiff ( idx1 , i );
			if ( diffbuf < diff ) diff = diffbuf;

		}
	}

	if ( bEnableCurrent ) {
		if (diff != -1 )return ( Current < diff ) ? Current : diff;
		return Current;
	}
	return diff;

}