#include<iostream>
#include<stdlib.h>
using namespace std;
const int N=100;
const int INF=0x3f3f3f3f;
int tree[N];
void preorder(int idx,int maxi,int& ans,int n){
    if(idx>=n)return;
    if(tree[idx]>=maxi)ans++;
    preorder(2*idx+1,max(maxi,tree[idx]),ans,n);
    preorder(2*idx+2,max(maxi,tree[idx]),ans,n);
}
int main(){
    int idx=0,n=0;
    string cur;
    while(cin>>cur){
        if(cur=="null")tree[idx++]=-1;
        else tree[idx++]=atoi(cur.c_str());
        n++;
    }
    int ans=0;
    preorder(0,-INF,ans,n);
    cout<<ans;
    return 0;
}