#pragma GCC optimize("Ofast")
// yukicoder@cpp
#include<bits/stdc++.h>
using namespace::std;
//struct __INIT{__INIT(){cin.tie(0);ios::sync_with_stdio(false);cout<<fixed<<setprecision(15);}} __init;
__attribute__((constructor))
void init(){
	cin.tie(0);
	ios::sync_with_stdio(false);
	cout<<fixed<<setprecision(15);
}
// random_device rd;
// mt19937 mt(rd());
// #include <boost/numeric/interval.hpp>
// #include <boost/numeric/interval/io.hpp>
// #include <boost/intrusive/rbtree.hpp>
// #include <boost/dynamic_bitset.hpp>
// #include <boost/geometry.hpp>
// #include <boost/geometry/geometries/linestring.hpp>
// #include <boost/geometry/geometries/polygon.hpp>
// #include <boost/geometry/geometries/point_xy.hpp>
// #include <boost/math/tools/minima.hpp>
// using boost::math::tools::brent_find_minima;
// #include <boost/multiprecision/cpp_dec_float.hpp>
// #include <boost/multiprecision/cpp_int.hpp>
// namespace mp = boost::multiprecision;
// typedef mp::number<mp::cpp_dec_float<256>> cdouble;
// typedef mp::cpp_int cint;

#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/priority_queue.hpp>
#include<ext/pb_ds/tag_and_trait.hpp>
template<typename T=long long>using pbds=__gnu_pbds::tree<T,__gnu_pbds::null_type,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T=long long>using pbds_map=__gnu_pbds::tree<T,T,less<T>,__gnu_pbds::rb_tree_tag,__gnu_pbds::tree_order_statistics_node_update>;
template<typename T=long long>using pqueue =__gnu_pbds::priority_queue<T, less<T>,__gnu_pbds::rc_binomial_heap_tag>;
typedef long long lint;
typedef long long ll;
typedef long double ldouble;
typedef vector<lint> vec;
typedef vector<vector<lint>> mat;
typedef vector<vector<vector<lint>>> mat3;
typedef vector<double> dvec;
typedef vector<vector<double>> dmat;
typedef vector<vector<vector<double>>> dmat3;
typedef vector<string> svec;
typedef vector<vector<string>> smat;
typedef vector<vector<vector<string>>> smat3;
typedef vector<pair<lint,lint>> pvec;
typedef vector<vector<pair<lint,lint>>> pmat;
typedef vector<vector<vector<pair<lint,lint>>>> pmat3;
#define rep(i, n) for(lint i = 0; i < (lint)(n); i++)
#define irep(i) for(lint i = 0;; i++)
#define irep1(i) for(lint i = 1;; i++)
#define irep2(i) for(lint i = 2;; i++)
#define rrep(i, n) for(lint i = (lint)(n-1); i >-1; i--)
#define rrepi(i,a,b) for(lint i = (lint)(b-1); i >a-1; i--)
#define repi(i,a,b) for(lint i=lint(a);i<lint(b);i++)
#define rep2(i,a,b,c) for(lint i=lint(a);i>lint(b);i+=c)
#define all(x) (x).begin(),(x).end()
#define PI 3.141592653589793
#define dist(x1,y1,x2,y2) (pow(pow(x2-x1,2)+pow(y2-y1,2),0.5))
#define input(a,n) lint n;cin>>n;vector<lint>a(n);rep(i,n)cin>>a[i];
#define SUM(v) accumulate(all(v),0LL)
#define INF (1LL<<60)
#define IINF (1<<30)
#define EPS (1e-10)
#define LINF 9223372036854775807
//#define MOD 998244353LL
#define MOD 1000000007LL
#define endl "\n"
template<typename T>inline void numout(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i<INF/2?i:"INF";f=1;}cout<<endl;}
template<typename T>inline void numout2(T t){for(auto i:t)numout(i);}
template<typename T>inline void output(T t){bool f=0;for(auto i:t){cout<<(f?" ":"")<<i;f=1;}cout<<endl;}
template<typename T>inline void output2(T t){for(auto i:t)output(i);}
template<typename T>inline void _output(T t){bool f=0;for(int i=0;i<t.size();i++){cout<<f?"":" "<<t[i];f=1;}cout<<endl;}
template<typename T>inline void _output2(T t){for(int i=0;i<t.size();i++)output(t[i]);}
auto Y=[&](auto f){return[&](auto... args){return f(f, args...);};};
template<typename T=lint>T in(){return *istream_iterator<T>(cin);}
template<typename T=lint>inline T gcd(T a,T b){return b?gcd(b,a%b):a;}
template<typename T=lint>inline T lcm(T a,T b){return a/gcd(a,b)*b;}
template<typename T=lint>inline T minq(T a,T b){return min(a,b);}
inline bool chmin(auto& s,const auto& t){bool res=s>t;s=min(s,t);return res;}
inline bool chmax(auto& s,const auto& t){bool res=s<t;s=max(s,t);return res;}
vector<lint> dx={-1,1,0,0,1,1,-1,-1};
vector<lint> dy={0,0,-1,1,1,-1,1,-1};

// #define rep(i, n) for(lint i = 0; i < (lint)(n); i++)
// template<typename K,typename V>class RBST{
//     struct node;using np=node*;
//     struct node{
//         np ch[2];K key;V val;
//         node(K key,V val):key(key),val(val){}
//     };
//     np root;
//     public:
//     int size(){return count(root);}
//     private:
    
//     np merge(np p,np q,np r){return merge(p,merge(q,r));}
//     tuple<np,np,np> split(np t,K l,K r){auto s=split(t,l);return make_tuple(s.first,split(s,r));}
//     mt19937 rnd(random_device());
//     np merge(vector<np> t,bool f=0){
//         if(f)swap(t[0],t[1]);
//         rep(i,2)if(!t[i])return t[1-i];
//         bool b=count(t[0])>rnd()%(count(t[0])+count(t[1]));
//         t[1-b]->ch[b]=merge(t[b],t[1-b]->ch[b],b);
//         return update(t[1-b]);
//     }
//     pair<np,np> split(np t,K k){
//         if(!t)return make_pair(nullptr,nullptr);
//         bool b=k>t->key;
//         auto s=split(t->ch[b],k);
//         t->ch[b]=b?s.first:s.second;
//         return b?make_pair(update(t),s.second):make_pair(s.first,update(t));
//     }
// };
random_device seed;
default_random_engine engine(seed());
negative_binomial_distribution<> rnd(1,0.5);
template<typename T>class SkipList{
    using P=T*;
    list<P> v[5];
    public:
    void push_back(T val){
        P p=new T(val); 
        rep(i,max(5,rnd(engine)+1))v[i].push_back(p);
    }
    void insert(T val){
        
    }
};
lint bs(lint mn,lint mx,function<bool(lint)> func) {
    lint left = mn-1;
    lint right =mx;
    while (right - left > 1) {
        lint mid = left + (right - left) / 2;
        if (!func(mid)) right = mid;
        else left = mid;
    }
    return left;
}
int main(){
    lint n;
    cin>>n;
    vec a(n);
    rep(i,n)cin>>a[i];
    rep(i,n-1)a[i+1]+=a[i];
    lint ans=0;
    rep(i,n)ans+=abs(a[i]-i-1);
    cout<<ans<<endl;
}