#include <bits/stdc++.h>
using namespace std;
int main(){
	int c=1,cnt=-1;
	int n,x;
	cin>>n;
	for (int i=1; i<=n;i++)
	{
		cin>>x;
		if (c==i)
		{
			c=c+x;
        	cnt++;
    	}
	}
	if (c==n)
	{
		cout<<"No"<<endl;
	} 
	else
	{
		cout<<"Yes"<<endl;
	}
	cout<<cnt<<endl;
	return 0;
}