#include <bits/stdc++.h>
using namespace std;
using ll=long long;

int main(){
    int N;
    cin>>N;
    vector<int> P(N);
    for(int i=0;i<N;i++){
        cin>>P[i];
    }
    int ans=0;
    for(int i=0;i<N;i++){
        if(i+1>P[i]) ans+=i+1;
        else if(i+1<P[i]) ans-=i+1;
    }
    cout<<ans<<endl;
    return 0;
}