#include <stdio.h>
#include <math.h>

int main(void) {
	int N, i, j, X[100001], dmin;
	scanf("%d", &N);
	for(i = 1;i <= N;i++){
		scanf("%d", &X[i]);
	}
	dmin = 1000001;
	for(i = 1;i <= N - 1;i++){
		for(j = i + 1;j <= N;j++){
			if(X[i] != X[j] && abs(X[i] - X[j]) < dmin)dmin = abs(X[i] - X[j]);
		}
	}
	if(dmin > 1000000)dmin = 0;
	printf("%d\n", dmin);

	return 0;
}