#include <vector>
#include <algorithm>
#include <iostream>
#include <utility>
 
using namespace std;
 
vector<pair<int, int>> v{ { 1, 3 }, { 2, 5 }, { 6, 9 } };
 
int solve(){
	vector<pair<int, int>> results;
 
	for (auto& vIndex : v){
		auto resultIndex = find_if(results.begin(), results.end(), [vIndex](const pair<int, int>& i){return vIndex.first >= i.first && vIndex.first <= i.second || vIndex.second >= i.first && vIndex.second <= i.second; });
 
		if (resultIndex == results.end()){
			results.push_back(vIndex);
		}else{
			resultIndex->first = min(vIndex.first, resultIndex->first);
			resultIndex->second = max(vIndex.second, resultIndex->second);
		}
	}
	return results.size();
}
 
int main(){
	cout << solve() << endl;
 
	return 0;
}

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