Ambuscada

#include <fstream>
#include <map>
std::ifstream fin ("ambuscada.in");
std::ofstream fout ("ambuscada.out");
int64_t n,m,v,l,r,k,ans,prev,sum;
std::map <int64_t,int64_t> Mars;

int main ()
{
    fin>>n>>m>>v;
    Mars[1]+=v,Mars[n+1]-=v;
    for(int64_t i=1;i<=m;++ i)
        fin>>l>>r>>k,Mars[l]-=k,Mars[r+1]+=k;
    for(auto it:Mars)
    {
        if(sum>0)
            ans+=it.first-prev-1;
        sum+=it.second,prev=it.first;
        if(sum>0)
            ++ans;
    }
    fout<<ans;
    return 0;
}