Given nonnegetive interger sequences a,b of length n . Let sl,r=∑i=lr∑j=iraibjs_{l,r}=sum_{i=l}^rsum_{j=i}^ra_ib_jsl,r=∑i=lr∑j=iraibj You need to calculate ans=mod998244353ans=leftbmod{998244353}ans=mod998244353
Given nonnegetive interger sequences a,b of length n . Let sl,r=∑i=lr∑j=iraibjs_{l,r}=sum_{i=l}^rsum_{j=i}^ra_ib_jsl,r=∑i=lr∑j=iraibj You need to calculate ans=(∑l=1n∑r=lnsl,r) mod 998244353ans=left(sumlimits_{l=1}^nsumlimits_{r=l}^ns_{l,r}right)bmod{998244353}ans=(l=1∑nr=l∑nsl,r)mod998244353
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