m,a[1<<17],s,n;c(const void*a,const void*b){return*(int*)a-*(int*)b;}main(){for(scanf("%d",&m);s<m;scanf("%d",a+s++));qsort(a,m,4,c);for(;--m;)if(s=a[m]-a[m-1])n=!n||s<n?s:n;m=!printf("%d",n);}