If don't know!

#include<bits/stdc++.h>
using namespace std;
long long h,w,mod=998244353;
long long qpow(long long k){
long long ans=1,a=2;
while(k){
if(k%2)ans=(ansa)%mod;
a=(aa)%mod;
k/=2;
}
return ans;
}
int main(){
cin>>h>>w;
cout<<qpow(((h%(mod-1))*(w%(mod-1)))%(mod-1))%mod;
}