int N,A[1d5];
mint dp[1d5],C[101][100],m[101]={}; 

{
  rd(N,A(N));
	dp[0]=1;
	rep(i,N){
    rep(d,1,100) dp[i]+=C[d][m[d]];
		if(i==N-1) break;
		if(A[i]==1) C[1][0]+=dp[i];
		else if(A[i]<=100) dp[i+1]+=dp[i], C[A[i]][m[A[i]]]+=dp[i];
		else{ dp[i+1]+=dp[i]; rep(j,i+A[i],N,A[i]) dp[j]+=dp[i]; }
		rep(d,1,100) m[d]+=1, if(m[d]==d) m[d]=0;
	}
	wt(dp[N-1]);
}