#include <bits/stdc++.h>
    using namespace std;
    #include <math.h>
    #include <iomanip>
    #include <cstdint>
    #include <string>
    #include <sstream>
    template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return 1; } return 0; }
    template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return 1; } return 0; }
    #define rep(i,n) for (int i = 0; i < (n); ++i)
    typedef long long ll;
    using P=pair<int,int>;
    const int INF=1001001001;
    const int mod=1e9+7;

    int main(){
      int n;cin>>n;
      vector<int>is(n+10,-1),c(n+10);
      rep(i,n){
        int a;
        cin>>a;
        is[a]=i;
      }
      int x=1,ans=0;
      while(x<=n){
        while(x<=n&&is[x]==-1||c[is[x]]){x++;}
        if(x>n){break;}
        ans++;
        c[max(0,is[x]-1)]=1;
        c[is[x]]=1;
        x++;
      }
      cout<<ans<<endl;
      return 0;
    }