Jolly Jumpers/정진경

Describe Jolly Jumpers/정진경 here

n,a,b,k,c[3000];main(){for(;scanf("%d%d",&n,&a)+1;printf(k-1?"Not j":"J"),puts("olly"))for(memset(c,0,n*4),k=n;--n;a=b){scanf("%d",&b);a=abs(a-b);if(!c[a])c[a]=1,k--;}}