#include<ctime>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<queue>
#include<vector>
#define p 998244353
#define rt register int
#define ll long long
using namespace std;
inline ll read(){ll x=0;char zf=1;char ch=getchar();while(ch!='-'&&!isdigit(ch))ch=getchar();if(ch=='-')zf=-1,ch=getchar();while(isdigit(ch))x=x*10+ch-'0',ch=getchar();return x*zf;
}
void write(ll y){if(y<0)putchar('-'),y=-y;if(y>9)write(y/10);putchar(y%10+48);}
void writeln(const ll y){write(y);putchar('\n');}
namespace poly{vector<int>R;int ksm(int x,int y=p-2){int ans=1;for(rt i=y;i;i>>=1,x=1ll*x*x%p)if(i&1)ans=1ll*ans*x%p;return ans;}void NTT(int n,vector<int>&A,int fla){A.resize(n);for(rt i=0;i<n;i++)if(i>R[i])swap(A[i],A[R[i]]);for(rt i=1;i<n;i<<=1){int w=ksm(3,(p-1)/2/i);for(rt j=0;j<n;j+=i<<1){int K=1;for(rt k=0;k<i;k++,K=1ll*K*w%p){int x=A[j+k],y=1ll*K*A[i+j+k]%p;A[j+k]=(x+y)%p,A[i+j+k]=(x-y)%p;}}}if(fla==-1){reverse(A.begin()+1,A.end());int invn=ksm(n);for(rt i=0;i<n;i++)A[i]=1ll*A[i]*invn%p;}}vector<int>Mul(vector<int>x,vector<int>y){int lim=1,sz=x.size()+y.size()-1;while(lim<=sz)lim<<=1;R.resize(lim);for(rt i=0;i<lim;i++)R[i]=(R[i>>1]>>1)|(i&1)*(lim>>1);NTT(lim,x,1);NTT(lim,y,1);for(rt i=0;i<lim;i++)x[i]=1ll*x[i]*y[i]%p;NTT(lim,x,-1);x.resize(sz);return x;}vector<int>sqr(vector<int>x){int lim=1,sz=x.size()*2-1;while(lim<=sz)lim<<=1;R.resize(lim);for(rt i=0;i<lim;i++)R[i]=(R[i>>1]>>1)|(i&1)*(lim>>1);NTT(lim,x,1);for(rt i=0;i<lim;i++)x[i]=1ll*x[i]*x[i]%p;NTT(lim,x,-1);x.resize(sz);return x;}vector<int>Inv(vector<int>A,int n=-1){if(n==-1)n=A.size();if(n==1)return vector<int>(1,ksm(A[0]));vector<int>b=Inv(A,(n+1)/2);int lim=1;while(lim<=n+n)lim<<=1;R.resize(lim);for(rt i=0;i<lim;i++)R[i]=(R[i>>1]>>1)|(i&1)*(lim>>1);A.resize(n);NTT(lim,A,1);NTT(lim,b,1);for(rt i=0;i<lim;i++)A[i]=1ll*b[i]*(2ll-1ll*A[i]*b[i]%p)%p;NTT(lim,A,-1);A.resize(n);return A;}vector<int>Div(vector<int>A,vector<int>B){int n=A.size(),m=B.size();reverse(A.begin(),A.end());reverse(B.begin(),B.end());A.resize(n-m+1),B.resize(n-m+1);int lim=1;while(lim<=2*(n-m+1))lim<<=1;R.resize(lim);for(rt i=0;i<lim;i++)R[i]=(R[i>>1]>>1)|(i&1)*(lim>>1);vector<int>ans=Mul(A,Inv(B));ans.resize(n-m+1);reverse(ans.begin(),ans.end());return ans;}vector<int>add(vector<int>A,vector<int>B){int len=max(A.size(),B.size());A.resize(len+1);for(rt i=0;i<=len;i++)(A[i]+=B[i])%=p;return A;}vector<int>sub(vector<int>A,vector<int>B){int len=max(A.size(),B.size());A.resize(len+1);for(rt i=0;i<=len;i++)(A[i]-=B[i])%=p;return A;}vector<int>Mod(vector<int>x,vector<int>y){if(x.size()<=y.size())return x;vector<int>ans=Div(x,y);ans=sub(x,Mul(y,ans));while(!ans[ans.size()-1])ans.pop_back();if(ans.size()>y.size())ans.resize(y.size());return ans;}
}
using namespace poly;
int a[100010];
vector<int>fmo;
vector<int>ksm(vector<int>x,int y){if(y==1)return x;vector<int>ans=Mod(sqr(ksm(x,y>>1)),fmo);if(y&1){ans.push_back(0);for(rt i=ans.size()-2;i>=0;i--)ans[i+1]=ans[i],ans[i]=0;}return ans;
}
using namespace poly;
int k,m,n,x,y,z,cnt,ans,K,P;
int f[1010][1010],mi[1010];
//f[i][j]长度为i合法高度最低至少为j的合法概率
void calc(int n,int K,int fla){memset(f,0,sizeof(f));for(rt i=0;i<=K+10;i++)f[0][i]=1;for(rt i=1;i<=K+2;i++)for(rt j=K/i;j>=0;j--){f[i][j]=1ll*f[i][j+1]*mi[i]%p;for(rt k=1;k<=i;k++)(f[i][j]+=1ll*f[k-1][j+1]*mi[k-1]%p*(1+p-P)%p*f[i-k][j]%p)%=p;}fmo.resize(K+2);for(rt j=1;j<=K+1;j++)fmo[K+1-j]=-1ll*mi[j-1]*f[j-1][1]%p*(p+1-P)%p;fmo[K+1]=1;int ret=0;if(n<=K+1)ret=f[n][0];else {vector<int>x;x.push_back(0);x.push_back(1);x=ksm(x,n);for(rt i=0;i<=K+1;i++)(ret+=1ll*f[i][0]*x[i]%p)%=p;}(ans+=ret*fla)%=p;
}
int main(){
//    file("pool");n=read();K=read();x=read();y=read();P=1ll*x*ksm(y)%p;mi[0]=1;for(rt i=1;i<=K+2;i++)mi[i]=1ll*mi[i-1]*P%p;calc(n,K,1);calc(n,K-1,-1);cout<<(ans+p)%p;return 0;
}