#include<bits/stdc++.h> using namespace std; int n; int a[200005]; int num[200005]; int l[200005],r[200005],cnt=0; int main(){ //freopen("sort.in","r",stdin); //freopen("sort.out","w",stdout); scanf("%d",&n); for(int i = 1;i<=n;i++){ scanf("%d",&a[i]);num[a[i]]=i;} for(int i = 1;i<=n;i++){ if(num[i]!=i){ cnt++; l[cnt]=num[i],r[cnt]=i; swap(a[num[i]],a[i]); num[a[num[i]]]=num[i]; num[i]=i; } } printf("%d\n",cnt); for(int i =1;i<=cnt;i++)printf("%d %d\n",min(l[i],r[i]),max(l[i],r[i])); //fclose(stdin); //fclose(stdout); } //O(n)