N,M,K,L=map(int,input().split())
result=0
mod=998244353
u=[1]*(M*K+N+1)
u2=[1]*(M*K+N+1)
for i in range(1,M*K+N+1):
  u[i]=u[i-1]*i
  u[i]%=mod
u2[M*K+N]=pow(u[M*K+N],-1,mod)
for i in range(M*K+N-1,-1,-1):
  u2[i]=u2[i+1]*(i+1)
  u2[i]%=mod
def ncm(x,y):
  if x<y or y<0:
    return 0
  ans=u[x]*u2[y]
  ans%=mod
  ans*=u2[x-y]
  ans%=mod
  return ans
for x in range(L,M+1):
  for a in range(N):
    ans=ncm(N-1,a)*pow(-1,a,mod)
    rest=M*K-x-a*(M+1)
    ans*=ncm(rest+N-2,N-2)
    result+=ans
    result%=mod
for x in range(L,M+1):
  for a in range(N):
    ans=ncm(N-1,a)*pow(-1,a,mod)
    rest=M*K-x-a*(x+1)
    ans*=ncm(rest+N-2,N-2)
    result-=ans
    result%=mod
print(result)