namespace AtCoder; #nullable enable using System.Numerics; readonly record struct ModInt : IEqualityOperators, IAdditiveIdentity, IAdditionOperators, IUnaryNegationOperators, ISubtractionOperators, IMultiplicativeIdentity, IMultiplyOperators, IDivisionOperators { int V { get; init; } public const int Mod = 998244353; public ModInt(long value) { var v = value % Mod; if (v < 0) v += Mod; V = (int)v; } ModInt(int value) { V = value; } public static implicit operator ModInt(long v) => new(v); public static implicit operator int(ModInt modInt) => modInt.V; public static ModInt operator +(ModInt a, ModInt b) { var v = a.V + b.V; if (v >= Mod) v -= Mod; return new(v); } public static ModInt operator -(ModInt a) => new(a.V == 0 ? 0 : Mod - a.V); public static ModInt operator -(ModInt a, ModInt b) { var v = a.V - b.V; if (v < 0) v += Mod; return new(v); } public static ModInt operator *(ModInt a, ModInt b) => new((int)((long)a.V * b.V % Mod)); public static ModInt operator /(ModInt a, ModInt b) { if (b == 0) throw new DivideByZeroException(); var (d, x, _) = ExtendedGcd(b.V, Mod); if (d > 1) throw new DivideByZeroException(); return x * a.V; } public ModInt Power(long p) { if (p < 0) return (MultiplicativeIdentity / V).Power(-p); long res = 1; long k = V; while (p > 0) { if ((p & 1) > 0) res = res * k % Mod; k = k * k % Mod; p >>= 1; } return res; } static (long d, long x, long y) ExtendedGcd(long a, long b) { if (b == 0) return (a, 1, 0); var (d, x, y) = ExtendedGcd(b, a % b); return (d, y, x - a / b * y); } public static ModInt AdditiveIdentity => new(0); public static ModInt MultiplicativeIdentity => new(1); public override string ToString() => V.ToString(); } static class Extensions { public static T[] Repeat(this int time, Func F) => Enumerable.Range(0, time).Select(_ => F()).ToArray(); } class AtCoder { object? Solve() { var n = Int(); var az = n.Repeat(Int); var max = 100000; var bc = 0; var mz = new int[n]; mz[0] = az[0]; for (var i = 1; i < n; i++) { var a = az[i]; var ap = az[i - 1]; if (ap >= a) { mz[i] = mz[i - 1]; bc += ap - a; } else { mz[i] = bc + a; } if (mz[i] > max) return 0; } var dp = new ModInt[max + 1]; var sp = new ModInt[max + 1]; for (var i = mz[0]; i <= max; i++) dp[i] = 1; sp[0] = dp[0]; for (var i = 1; i <= max; i++) sp[i] = dp[i] + sp[i - 1]; for (var i = 1; i < n; i++) { var ep = new ModInt[max + 1]; var m = mz[i]; var d = m - mz[i - 1]; for (var j = d; j <= max; j++) { ep[j] += sp[j - d]; } var tp = new ModInt[max + 1]; tp[0] = ep[0]; for (var j = 1; j <= max; j++) tp[j] = ep[j] + tp[j - 1]; (dp, sp) = (ep, tp); } var ans = sp[max]; return ans; } public static void Main() => new AtCoder().Run(); public void Run() { var res = Solve(); if (res != null) { if (res is bool yes) res = yes ? "Yes" : "No"; sw.WriteLine(res); } sw.Flush(); } string[] input = Array.Empty(); int iter = 0; readonly StreamWriter sw = new(Console.OpenStandardOutput()) { AutoFlush = false }; #pragma warning disable IDE0051 string String() { while (iter >= input.Length) (input, iter) = (Console.ReadLine()!.Split(' '), 0); return input[iter++]; } T Input() where T : IParsable => T.Parse(String(), null); int Int() => Input(); void Out(object? x, string? separator = null) { separator ??= Environment.NewLine; if (x is System.Collections.IEnumerable obj and not string) { var firstLine = true; foreach (var item in obj) { if (!firstLine) sw.Write(separator); firstLine = false; sw.Write(item); } } else sw.Write(x); sw.WriteLine(); } #pragma warning restore IDE0051 }