Submission

Score: 0

User: nunos

Problemset: ห้องสมุดเมือง 3M

Language: cpp

Time: 0.003 second

Submitted On: 2025-10-04 13:13:09

#include <iostream>
#include <map>
#include <algorithm>
using namespace std;
typedef unsigned long long int ll;

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    ll minn = 0;
    ll sum=0;
    int n;cin>>n;
    for(int i=0;i<n;i++){
        ll a,b;cin>>a>>b;
        if(minn>=a){
            sum += (b-minn);
            minn = b;
        }else{
            sum += (b-a);
            minn=b;
        }
    }
    if(sum%2==0) cout << sum/2;
    else cout << (sum/2)-1 << "\n";
    return 0;
}