#include<bits/stdc++.h> using namespace std; int n,a[100001],b[100001],dp[100001]; int main(){ memset(dp,0,sizeof(dp)); cin>>n; for(int i=1;i<=n;i++){ cin>>a[i]>>b[i]; } for(int i=1;i<=n;i++){ for(int j=1;j<=n;j++){ if(a[j]<=a[i]&&a[j]>=b[i]||a[j]>=a[i]&&b[j]<=b[i]){ dp[i]=max(dp[i],dp[j]+1); } } } int maxn=9e9; for(int i=1;i<=n;i++){ maxn=min(maxn,dp[i]); } cout<<n-maxn-1; return 0; }