#include <stdio.h>
int main(void){
    int n;
    scanf( "%d", &n );

    int i, j;
    int x;
    //int pos[n];
    char pos[1000000];
    int max = 0;
    long min = 1000001;
    int d = 0;
    int from = -1;

    for( i = 0; i <= 1000000; i++ ){
        pos[i] = 'o';
    }
    for( i = 0; i < n; i++ ){
        scanf( "%d", &x );
        pos[x] = 'x';
        if( x > max  ){
            max = x;
        }
    }

    for( i = 0; i <= max; i++ ){
        if( pos[i] == 'x' ){
            if( from < 0 ){
                from = i;
            }else{
                d = i - from;
                if( d > 0 && d < min ){
                    min = d;
                }
            }
        }
    }
    printf( "%d\n", ( min == 1000001 ) ? 0 : min );
}