ll@n,@a[n],z=0,d[2001][2012]{},e[][]{}; rep(i,n){ d[i+1][0..2011]=d[i][0..]; d[i+1][a[i]+10]+=1; } rrep(i,n){ e[i][0..2011]=e[i+1][0..]; e[i][a[i]]+=1; } rep(x,1,n-2){ rep(y,x+1,n-1){ if(a[x]>a[y]){ z+=d[x][a[y]]*e[y+1][a[x]+1]; } } } wt(z);