import sys # sys.setrecursionlimit(200005) # sys.set_int_max_str_digits(200005) int1 = lambda x: int(x)-1 pDB = lambda *x: print(*x, end="\n", file=sys.stderr) p2D = lambda x: print(*x, sep="\n", end="\n\n", file=sys.stderr) def II(): return int(sys.stdin.readline()) def LI(): return list(map(int, sys.stdin.readline().split())) def LLI(rows_number): return [LI() for _ in range(rows_number)] def LI1(): return list(map(int1, sys.stdin.readline().split())) def LLI1(rows_number): return [LI1() for _ in range(rows_number)] def SI(): return sys.stdin.readline().rstrip() dij = [(0, 1), (-1, 0), (0, -1), (1, 0)] # dij = [(0, 1), (-1, 0), (0, -1), (1, 0), (1, 1), (1, -1), (-1, 1), (-1, -1)] # inf = -1-(-1 << 31) inf = -1-(-1 << 62) # md = 10**9+7 md = 998244353 class LazySegTree: def __init__(self, op, e, mapping, composition, _id, v): self._op = op self._e = e self._mapping = mapping self._composition = composition self._id = _id if isinstance(v, int): v = [e]*v self._n = len(v) self._log = (self._n-1).bit_length() self._size = 1 << self._log self._d = [self._e]*(2*self._size) self._lz = [self._id]*self._size for i in range(self._n): self._d[self._size+i] = v[i] for i in range(self._size-1, 0, -1): self._update(i) def set(self, p, x): p += self._size for i in range(self._log, 0, -1): self._push(p >> i) self._d[p] = x for i in range(1, self._log+1): self._update(p >> i) def get(self, p): p += self._size for i in range(self._log, 0, -1): self._push(p >> i) return self._d[p] def prod(self, left, right): if left == right: return self._e left += self._size right += self._size for i in range(self._log, 0, -1): if ((left >> i) << i) != left: self._push(left >> i) if ((right >> i) << i) != right: self._push(right >> i) sml = self._e smr = self._e while left < right: if left & 1: sml = self._op(sml, self._d[left]) left += 1 if right & 1: right -= 1 smr = self._op(self._d[right], smr) left >>= 1 right >>= 1 return self._op(sml, smr) def all_prod(self): return self._d[1] def apply(self, left, right, f): if right is None: p = left p += self._size for i in range(self._log, 0, -1): self._push(p >> i) self._d[p] = self._mapping(f, self._d[p]) for i in range(1, self._log+1): self._update(p >> i) else: if left == right: return left += self._size right += self._size for i in range(self._log, 0, -1): if ((left >> i) << i) != left: self._push(left >> i) if ((right >> i) << i) != right: self._push((right-1) >> i) l2 = left r2 = right while left < right: if left & 1: self._all_apply(left, f) left += 1 if right & 1: right -= 1 self._all_apply(right, f) left >>= 1 right >>= 1 left = l2 right = r2 for i in range(1, self._log+1): if ((left >> i) << i) != left: self._update(left >> i) if ((right >> i) << i) != right: self._update((right-1) >> i) def max_right(self, left, g): if left == self._n: return self._n left += self._size for i in range(self._log, 0, -1): self._push(left >> i) sm = self._e first = True while first or (left & -left) != left: first = False while left%2 == 0: left >>= 1 if not g(self._op(sm, self._d[left])): while left < self._size: self._push(left) left *= 2 if g(self._op(sm, self._d[left])): sm = self._op(sm, self._d[left]) left += 1 return left-self._size sm = self._op(sm, self._d[left]) left += 1 return self._n def min_left(self, right, g): if right == 0: return 0 right += self._size for i in range(self._log, 0, -1): self._push((right-1) >> i) sm = self._e first = True while first or (right & -right) != right: first = False right -= 1 while right > 1 and right%2: right >>= 1 if not g(self._op(self._d[right], sm)): while right < self._size: self._push(right) right = 2*right+1 if g(self._op(self._d[right], sm)): sm = self._op(self._d[right], sm) right -= 1 return right+1-self._size sm = self._op(self._d[right], sm) return 0 def _update(self, k): self._d[k] = self._op(self._d[2*k], self._d[2*k+1]) def _all_apply(self, k, f): self._d[k] = self._mapping(f, self._d[k]) if k < self._size: self._lz[k] = self._composition(f, self._lz[k]) def _push(self, k): self._all_apply(2*k, self._lz[k]) self._all_apply(2*k+1, self._lz[k]) self._lz[k] = self._id # treeのマージ # 32bit以上を区間長とした例 def op(x, y): return x+y # treeの単位元 e = 0 # lazy(f)からtree(x)への操作 def mapping(f, x): if f==None:return x c=x%(1<<20) return (f*c)<<20|c # lazyの下への分解 def composition(f, g): if f==None:return g return f # lazyの単位元 _id = None # 配列の初期値(サイズか配列そのもの)が最後 n=II() aa=LI() mns = LazySegTree(op, e, mapping, composition, _id, [1]*n) mxs = LazySegTree(op, e, mapping, composition, _id, [1]*n) mn=[] mx=[] s=0 ans=0 for i,a in enumerate(aa): c=1 l=i t=0 while mn and mn[-1][0]>=a: pa,pc=mn.pop() l-=pc cur=mxs.prod(l,l+pc)>>20 s-=pa*cur%md c+=pc t+=cur s+=t*a%md mns.apply(l,i+1,a) mn.append((a,c)) c=1 l=i t=0 while mx and mx[-1][0]<=a: pa,pc=mx.pop() l-=pc cur=mns.prod(l,l+pc)>>20 s-=pa*cur%md c+=pc t+=cur s+=t*a%md mxs.apply(l,i+1,a) mx.append((a,c)) s+=a*a ans+=s s%=md ans%=md # print(i,a,s,ans,mn,mx) print(ans)