S=sum(i=0,t-1) sum(j=i+1,t) sum(k=j,t-1) 1=sum(i=0,t-1) T=sum(i=0,t-1)(((t-i-1)*(t-i))/2)=1/2*sum(i=0,t-1)(((t-i)-1)*(t-i))

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