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

#undef _P
#define _P(...) (void)printf(__VA_ARGS__)
#define FOR(x,to) for(x=0;x<(to);x++)
#define FORR(x,arr) for(auto& x:arr)
#define ITR(x,c) for(__typeof(c.begin()) x=c.begin();x!=c.end();x++)
#define ALL(a) (a.begin()),(a.end())
#define ZERO(a) memset(a,0,sizeof(a))
#define MINUS(a) memset(a,0xff,sizeof(a))
//-------------------------------------------------------

template<class V, int ME> class BIT {
public:
	V bit[1<<ME];
	V operator()(int e) {if(e<0) return 0;V s=0;e++;while(e) s+=bit[e-1],e-=e&-e; return s;}
	void add(int e,V v) { e++; while(e<=1<<ME) bit[e-1]+=v,e+=e&-e;}
};
BIT<int,20> bt;

int N;
int M[303030];
ll ret;

void solve() {
	int i,j,k,l,r,x,y; string s;
	
	cin>>N;
	for(i=1;i<=N;i++) {
		cin>>M[i];
		if(M[i]>=i) {
			bt.add(M[i],1);
		}
		else {
			ret+=bt(N)-bt(M[i]-1);
		}
	}
	ZERO(bt.bit);
	for(i=N;i>=1;i--) if(M[i]>=i) {
		ret+=bt(M[i]);
		bt.add(M[i],1);
	}
	ZERO(bt.bit);
	for(i=1;i<=N;i++) if(M[i]<i) {
		ret+=bt(N)-bt(M[i]);
		bt.add(M[i],1);
	}
	cout<<ret<<endl;
	
}


int main(int argc,char** argv){
	string s;int i;
	if(argc==1) ios::sync_with_stdio(false), cin.tie(0);
	FOR(i,argc-1) s+=argv[i+1],s+='\n'; FOR(i,s.size()) ungetc(s[s.size()-1-i],stdin);
	cout.tie(0); solve(); return 0;
}