#include <cstdio>
#include <vector>
#include <set>
#include <queue>
using std::vector;
using std::set;
using std::priority_queue;

struct Node{
	int d;
	int need;
	int t;
	bool operator < (const Node& other) const{
		return d < other.d;
	}
};

int main(){
	int n;
	scanf("%d",&n);
	vector<int> a(n);
	long long ans = 0;
	for(int i = 1; i <= n; i++){
		int u;
		scanf("%d",&u);
		if(u != i){
			if(u>i) ans -= 1ll*i;
			else ans += 1ll*i;
		}
	}
	printf("%lld\n",ans);
	return 0;
}