Compilare: main.cpp:2:45: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type] int i,n,k,a;std::pair<int,int>v[1<<17];main(){std::fstream I("int.in");std::ofstream O("int.out");I>>n;for(i=0;i<n;++i)I>>v[i].second>>v[i].first;std::sort(v,v+n);for(;k<n;++a)for(i=k++;k<n&&v[k].second<v[i].first;++k);O<<a;} ^